severe miss under load, popping, cracking while in the throttle

Stangman

Stangman

Project car a.d.d.
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Sardinia, OH
Figured I'd try and see if anyone else is having this problem on their first gen with OBD1

When my car is cold, as in, just started, let it idle for a few, then put it in gear and go, I can "try" to stand on it and it will buck, and hessitate, and pop and crack as it get's higher in the RPM's in first...

I let off and it will shift into second, and all seems normal unless I were to stand on it again.

Now once it gets warmed up, I can stand on it and it will shift, may hessiate a little bit or pop and crack but it will not buck and basically say "EFF YOU"

But now if I were cruising it on the highway and stand in it, it will upshift, and start to go, but then once again it will pop, crack and just feel like all the power is not there. Every soo often I can actually feel the car "open up". But of course within seconds it's acting up and I cant feel the true power of the car.

Now, Before you start telling me check this and check that, and replace this and replace that...

I have replaced the spark plugs with some good ones from NGK, I have MSD wires, new coil packs, new fuel filter, I have seafoamed the car 3 times. cleaned the MAF and the T/B... I have also tested the fuel pressure and replaced the o2 sensors. I am at a loss. I have no idea what this things deal is....

My car would be absolutely nasty wild if it would just show it's true nature and not act up...

Please help.

thank you.:)
 
OBDI codes are about as useful as :q:q:q:q on a bull. You need to pull your plugs one at a time (all of them) and check their condition. See if one shows unusual wear or blackening. It could be a coil gone bad that works when heated up. Beyond that, I don't see a need for more seafoam (i personall think the stuff is :q:q:q:q in a bottle) Make sure you're cats aren't clogging either, a laser thermometer can check that. Also check vac lines and intake, make sure their all good and tight, no leaks. A hot engine can compensate for some problems that a cold one cannot. EGR is also a probable culprit
 
Same Problem

Hey, I got the same problem. I don't know hot to clean the T/B though. But I have screamin demon coil packs (3 years old). Live wire wires (3 years old ). Discovered a hole in the intake tube from the air filter. Didn't fix it but helped. Cleaned the K&N filter. Replaced the gaskets on my exhaust flanges. Had a gassy smelll in the cabin. After looking around more, found a clicking comin from near the enginge by the steering wheel column. Found some heat wrapping flapping in the exhaust wind. From what I've discovered, it's the EGR exhaust/intake tube. There is a coil flex tube in the middle. This tube goes from the colleector of the manifold and to the intake somewhere. I tried plugging up the leak with exhaust patch. It helped alot with the sound but I still have that same problem you mentioning. I need to figure out how to clean the T/B. I haven't tried that yet. Post what your findings are . . . :cool:
 
I had o2 sensor codes and the neutral safety switch code before, replaced o2's and the shift sensor and havent checked them yet, light comes on occasionally still

The car is straight-piped. No cats whatsoever nor mufflers or resonators. My exhaust is as free-flowing as it gets.

no EGR codes. The EGR flex-pipe has been replaced, and was replaced when the trans was replaced a few months ago.

The car has done this since day 1.
 
I have a similar problem like yours. But its not when my car is cold it just happens out of nowhere. I can mash my foot all the way down on the pedal and nothing will happen, but then out of nowhere it will pick up and show its HP/TQ. I put new plugs/wires/air/fuel filters. The only thing that helped a little was the fuel filter. I do have a cel at times but do not now how to check OBD1. I had the scanner but there was a problem with the obd1 port on the car. I made a thread about that last year. Maybe I will buy another scanner and spend an hour and just try each way because this bogging down issue I have is really annoying.
 
Sounds like a nasty problem.
Because it starts and seems to idle fine makes me think its not spark related.
But I agree with stang99x on pulling the plugs and taking a look at them.
I would take a fuel pressure gage and hook it up to the schrader valve on the fuel rail and run it up so I could shut the hood and check pressure while I stand on it while driving it.
 
ford nut said:
I would take a fuel pressure gage and hook it up to the schrader valve on the fuel rail and run it up so I could shut the hood and check pressure while I stand on it while driving it.
Click to expand...

+2 id look for a fuel supply prob, do like nut stated above and see what psi your running at WOT under a load
 
I'll try it... but I find that hard to be able to do while driving...

I can sit in my driveway in park and free-rev it all day long and it doesnt really act up...
 
Run it up and use the wiper to hold it down, if you can't see it have a buddy ride along and watch it.
It might not solve the problem but if pressure stays up you can check fuel pressure off the list.
 
yeah and its been over 2 years since a markviii rolled throught the door, and i dont remember crap like that off the top of my head, espically after drinking since 6pm
 
Assuming it has quite a few miles on it, the straight pipe could be causing a lack of backpressure at times when cold and make that kind of issue. Its really hard to diagnose without seeing it though. Like I said, check the plugs and fuel pressure, maybe one cylinder is loading up cold:confused:
 
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