Mark VIII started jerking today

D

drobs5

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So today I was travelling to a friends house driving along normal when I got caught behind a school bus travelling about 35 or 40 mph. As we started making our way up a decent size hill, I noticed my car was lugging a bit and felt like it needed to kick down a gear. Just after noticing this, it kicked down in third and then started jerking almost as if it was bouncing between gears or between the converter being locked up or not. I made it to my friends house with the car randomly jerking from time to time here and there thinking hopefully it would throw a check engine light to help me diagnose the problem but no luck. Anyway, I was able to make it back home (about a 30 min drive) with the car randomly jerking from time to time but still no check engine light. Whatever is wrong with it has also affected the idle as now the car seems to hunt or idle search when in drive. I can still feel what feels like slight miss when idling in neutral but the car doesn't idle hunt in neutral.

So what does everyone think may be the culprit here? I haven't had any problems with the car in the 6 months I've owned it prior to this but I also haven't done any routine maintenance other than changing the oil. I figured I would start with the basic plug and plug wire change although it seems like I would get a CEL if a misfire were my problem. I thought I'd also try a fuel filter just because I don't know the last time it was changed. And last but not least, I thought I might try draining the trans fluid and replacing it. Outside of that, what could it be? I thought maybe the tps but I monitored the tps % via my OBD bluetooth adapter and torque adapter and it seemed normal although I'm not sure there is enough resolution for me to see the blip/jerk as it happens so quickly.

Any thoughts? All help is appreciated as this is my daily driver and want to get it back running right as soon as possible.
 
drobs5 said:
So today I was travelling to a friends house driving along normal when I got caught behind a school bus travelling about 35 or 40 mph. As we started making our way up a decent size hill, I noticed my car was lugging a bit and felt like it needed to kick down a gear. Just after noticing this, it kicked down in third and then started jerking almost as if it was bouncing between gears or between the converter being locked up or not. I made it to my friends house with the car randomly jerking from time to time here and there thinking hopefully it would throw a check engine light to help me diagnose the problem but no luck. Anyway, I was able to make it back home (about a 30 min drive) with the car randomly jerking from time to time but still no check engine light. Whatever is wrong with it has also affected the idle as now the car seems to hunt or idle search when in drive. I can still feel what feels like slight miss when idling in neutral but the car doesn't idle hunt in neutral.

So what does everyone think may be the culprit here? I haven't had any problems with the car in the 6 months I've owned it prior to this but I also haven't done any routine maintenance other than changing the oil. I figured I would start with the basic plug and plug wire change although it seems like I would get a CEL if a misfire were my problem. I thought I'd also try a fuel filter just because I don't know the last time it was changed. And last but not least, I thought I might try draining the trans fluid and replacing it. Outside of that, what could it be? I thought maybe the tps but I monitored the tps % via my OBD bluetooth adapter and torque adapter and it seemed normal although I'm not sure there is enough resolution for me to see the blip/jerk as it happens so quickly.

Any thoughts? All help is appreciated as this is my daily driver and want to get it back running right as soon as possible.
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need to tell us what year car you have-does the tach needle bounce when this happens?
 
It's a 97 and I dont remember the tach moving when it happened while driving. It happens so quickly that I'm not sure the tach could even react that fast. I definitely noticed the tach changing when it was happening at idle though. I'll take it for a drive and report back, maybe with a video.

Are any of the plug wires that the local auto parts house stock worth a crap? Normally I use mad or ford racing wires on my cars but was hoping to find some this weekend and not have to wait on a set to be shipped to me.
 
You dont have plug wires, but it does sound like a COP.

Check codes.
 
I fought a bad COP for a few weeks before it finally set a code.

It seems like I am possibly getting back into the same issue. My 97 is fine when cold and short trips, but longer trips with variable speed/load I get a lurch/stutter on attempts to accelerate. I have been trying to use the misfire detection PIDs but am not sure that works with our cars.
 
Still no codes so I pulled the plugs and cop's a little bit ago. There were a mix of what appear to be original motorcraft cop's and no name brand cops that has been installed on the car sometime during it's life. The car has 110,000 miles on it so I assume it's a good time to just replace all the cop's so I don't have to worry about one here or there causing me a problem for the remaining time that I own the car. I imagine these aren't cheap though (haven't googled them yet). Is there a performance version that people normally use or do people normally just use oem ford cop's?

With that said I fear I have a bigger problem/headache. Each one of the cop's had a little oil on the outside of the boot and #8 actually had oil inside the boot. I was afraid this might be the case since I was travelling up hill when the problem started and had been noticing a slight smell of burning oil from time to time. The valve cover gaskets are a pretty big pita to replace right? I think I remember reading this here in the past. Being that I need to get it back on the road I may try cleaning the oil, replacing the plugs and replacing the #8 cop until I get my truck back on the road as a dd and then I can do the gaskets and new, quality cop's. Thoughts?
 
Well after my last post I decided to go ahead and replace the valve cover gaskets as spark plug holes number 6 and 8 were full of oil. So far I've been able to get the passenger side off (had to jack up the engine on that side to get it off so I guess the motor mount is also wore out on that side) and will start on the driver side after a short break. Is the FEL pro replacement gasket that autozone sells any good or should I stick with the oem gasket?
 
On my 97 one COP went bad, and It felt just like a trans problem. On the drivers side the valve cover gasket is a little harder. You have to move, not disconnect, the master cylinder. Sounds like your doing all the right things. A trans oil change, would be good if you don't have any records on it. Mercon 5.
 
Well I was able to get both sides off today and holy crap the stuff I had to remove/move on the driver side. Dang thing will probably never run right again after all the stuff I removed and moved out of the way. Hopefully tomorrow I'll be getting both sides back on and then some new cop's early in the week. Are the accel cop's sold for these cars any good?
 
drobs5 said:
Well I was able to get both sides off today and holy crap the stuff I had to remove/move on the driver side. Dang thing will probably never run right again after all the stuff I removed and moved out of the way. Hopefully tomorrow I'll be getting both sides back on and then some new cop's early in the week. Are the accel cop's sold for these cars any good?
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Accels are middle of the road, nothing special that warrants the price over regular coils.

I agree with Tony, a bad cop can make you think the trans is having issues. It reminds me of torque shudder (Rumble strips).
 
what about the msd coils?

Got the valve covers back on a little bit ago, now just have to reassemble everything I took off to get the driver side valve cover off. Woot! I sure hope this foxes my problem.
 
msd = misses, sputters, dies. my spark disappeared, etc etc. OEM does just fine. and will last longer too.
 
By oem do you mean motorcraft cuz they are freaking expensive. Surely there is another option?
 
BWD seems to be pretty good.

http://shop.advanceautoparts.com/p/...p/18240244-P?navigationPath=L1*14923|L2*15034

My recenty purchased DD did the same to me last week on my way home from work and tossed me a check engine light just as I got home. P0303 Cylinder 3 Misfire.

I have a former DD that is down for the count due to a recent wreck that I initially wanted to swap a COP and spark plug from since I recently tuned it up with OEM COPs & plugs. However I couldn't open the hood so I went with a quick BWD COP & OEM plug from Advanced Auto Parts and the DD has been going smooth thus far.

I want to tune up the WF since I just purchased it as my new DD and so now my battle is whether I want to swap the recently installed(Sept '14) OEM stuff into the new DD or hold 'em as back up and go with 7 more BWD COPs and 7 more Motorcraft spark plugs(SP-433).
 
After reading the reviews of aftermarket cop's and looking at the price of motorcraft cop's I decided to clean my current ones and reinstall them with hopes they would be ok. After a quick test drive, everything seems to be normal ftw!
 
It started again on the way to work this morning ftl. Luckily I was able to datalog the misfires with my phone (through the bluetooth obd adapter and android torque app) and sure enough #8 is misfiring alot. So I guess I'll order a single motorcraft coil tonight. It's weird because it only does it at idle that I can tell which made me think my alternator output might be low but I guess that is just the sign of a bad coil. My alternator is showing anywhere from mid 12 to 13v at idle which I thought was a little low. I was expecting to see closer to 14v.
 
drobs5 said:
It started again on the way to work this morning ftl. Luckily I was able to datalog the misfires with my phone (through the bluetooth obd adapter and android torque app) and sure enough #8 is misfiring alot. So I guess I'll order a single motorcraft coil tonight. It's weird because it only does it at idle that I can tell which made me think my alternator output might be low but I guess that is just the sign of a bad coil. My alternator is showing anywhere from mid 12 to 13v at idle which I thought was a little low. I was expecting to see closer to 14v.
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Warm idle it should read above 13.5v, 13.8+ ideally. I'd take a good look at your terminals and grounds and clean them if necessary. If that doesn't do I would take both in to get tested.
 
My battery has left me stranded a couple times in the past 6 months. Both times I still had power to run the lights, radio, etc but when I try to start the car, all I would get is a clicking noise. It would seem like this would point to a loose or bad connection but the terminals are good and tight with no corrosion. Each time I have removed the battery and charged it overnight and then it's been good to go for another few months. It's possible I have a bad cell in the battery or that the alternator is struggling. Not sure what's going on ... I'll replace the #8 cop and hopefully the misfire goes away. Then I'll worry about the voltage.
 
drobs5 said:
My battery has left me stranded a couple times in the past 6 months. Both times I still had power to run the lights, radio, etc but when I try to start the car, all I would get is a clicking noise. It would seem like this would point to a loose or bad connection but the terminals are good and tight with no corrosion. Each time I have removed the battery and charged it overnight and then it's been good to go for another few months. It's possible I have a bad cell in the battery or that the alternator is struggling. Not sure what's going on ... I'll replace the #8 cop and hopefully the misfire goes away. Then I'll worry about the voltage.
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The battery might be dragging down the alt giving you those readings.
 
After the coil arrives and I swap it in and hopefully fixes the misfire, I'll try swapping the battery out of my truck into the MK8 to see if the idle voltage reads any higher.
 
Replaced #8 coil with a motorcraft unit (made in china) and took it for a test drive ... it appears my misfire is now gone. I then proceeded to check my battery voltage while running (and warm). It was right at 12v at idle in gear. I tried swapping in a different battery and it read the same. So I guess I'll be pulling the alternator this weekend to have it tested or just rebuild it ftl.
 
Glad to hear you cleared up the misfire issue, and I believe I may be able to shed a bit of insight on this charging system scenario. When I took my '96 out of storage last April, I originally fitted it with an older Everstart(Walmart) battery, age unknown, out of my equally old Ranger. Of course, it ran the Ranger alright, though I assume it takes a bit more juice to maintain a 4.6L DOHC and all of the luxury fixings than it does to start and operate a 2.3L Lima. But I thought nothing of it, and drove the car that way for three weeks UNTIL -

I was making a 100 mile trip to my parents house to the north of me, and stopped at a rest area at about the halfway point for a leak, and upon hitting the key to hit the road again, it turned over very slowly, but started, and ran fine. I had my suspicions at that point that I had some charging system fault, and surely enough about three miles down the interstate, the power options began leaving me, slow at first, then progressively more. The tachometer, the stereo, all interior illumination. I pulled off and shut it down, had it towed to my folks for diagnosis, which I was sure was an alternator failure, and it was. I did a relatively smart thing while changing in that new alternator however, and replaced the battery with a solid, brand new unit as well.

The moral of this story, is that the charging system is more sensitive to faults than you may think. On an older pickup, it may never give an issue, but a bad battery, or even a questionable battery in my case, ruined my original Motorcraft alternator in less than 20 days. And I'm near sure this is what has happened to you, your alternator is probably giving up the ghost. When you do swap that alt, make sure you swap a new battery in at the SAME TIME. Your charging system will thank you for it in the long run.
 
drobs5 said:
My battery has left me stranded a couple times in the past 6 months. Both times I still had power to run the lights, radio, etc but when I try to start the car, all I would get is a clicking noise. It would seem like this would point to a loose or bad connection but the terminals are good and tight with no corrosion. Each time I have removed the battery and charged it overnight and then it's been good to go for another few months. It's possible I have a bad cell in the battery or that the alternator is struggling. Not sure what's going on ... I'll replace the #8 cop and hopefully the misfire goes away. Then I'll worry about the voltage.
Click to expand...

Could be an alt. getting ready to go bad as well, same happened to me.
 
Is there an alternator rebuild kit you can get and do it yourself or do you just have to buy a new one?
 
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