Another shudder thread, but this appears to be different

[Mechanicboy]

My mark 8 has a shudder that occurs 80% of the time but the other 20% it's smooth.

It does it in any gear, any throttle condition and sometimes seems to shake at idle. Usually it doesn't do it at WOT but sometimes it shakes super bad at WOT. When it shakes bad it has a sort-of booming/rattle sound to it, could just be from shaking the whole car though. The transmission shifts great but is occasionally slow shifting into Drive, it's usually a quart low on fluid when this happen.

I've check the converter bolts and they are great and the flywheel bolts seem to be great too. The only play I can find here is in the crank end-play. The rear main seal on the engine and front main on the trans don't leak.

I thought maybe it was a miss-fire so when it was doing it at idle I disconnected head plug wire and each one produced the same change in idle leading me to believe that's not the problem, plus it has good power and no codes.

The fluid is bright red but I think the previous owner used that cheap mercon/dextron fluid in it because it has a leak at the fill tube (appears to be an O-ring is bad, or at least I hope). I've been adding mercon V. I'm told they are compatible but I've always done complete flushes in the past. I don't want to waste my time/money flushing the system if the converter is screwed.

Any advice is appreciated.

Edit, it's a 1996 base model.

 

[Lownslowlsc]

My mark 8 has a shudder that occurs 80% of the time but the other 20% it's smooth.

It does it in any gear, any throttle condition and sometimes seems to shake at idle. Usually it doesn't do it at WOT but sometimes it shakes super bad at WOT. When it shakes bad it has a sort-of booming/rattle sound to it, could just be from shaking the whole car though. The transmission shifts great but is occasionally slow shifting into Drive, it's usually a quart low on fluid when this happen.

I've check the converter bolts and they are great and the flywheel bolts seem to be great too. The only play I can find here is in the crank end-play. The rear main seal on the engine and front main on the trans don't leak.

I thought maybe it was a miss-fire so when it was doing it at idle I disconnected head plug wire and each one produced the same change in idle leading me to believe that's not the problem, plus it has good power and no codes.

The fluid is bright red but I think the previous owner used that cheap mercon/dextron fluid in it because it has a leak at the fill tube (appears to be an O-ring is bad, or at least I hope). I've been adding mercon V. I'm told they are compatible but I've always done complete flushes in the past. I don't want to waste my time/money flushing the system if the converter is screwed.

Any advice is appreciated.

Dr. Tranny Instant trans shudder fix. Stuff is amazing and about 6.50 shipped on ebay. Better then dropping a benji on a flush n' fill.

But it sounds like you need a tuneup, and bad.

Gen one or two?

 

[Mechanicboy]

Dr. Tranny Instant trans shudder fix. Stuff is amazing and about 6.50 shipped on ebay. Better then dropping a benji on a flush n' fill.

But it sounds like you need a tuneup, and bad.

Gen one or two?

Forgot, it's a 96' so gen 1.

I'm not looking to do a quick fix as I'm going to be giving this to my mom so I want to do it right.

When I think tune-up, I think engine, are you referring to the trans?

 

[Lownslowlsc]

The Dr. Tranny (Friction modifier) suggestion was more of a "put it in and see if that's the issue" type of thing before you flush her out with V. I however have been running it for years without the shudder returning. Since yours is happening at all speeds I honestly don't think that's the problem.

I'm referring to the motor. If it were me I'd start with plugs and wires. Some of the gen1 guys might be more familiar with said issue so I'd wait for some of their opinions.

 

[chris2523]

dexron/mercon shouldn't be used, mercon v should.
dr tranny helps some people, but this doesn't really sound like a trans issue.

plugs and wires been changed recently?
autolite 764 plugs gapped to .050-.054, and ford wires work fine, and are not terribly expensive.

any codes? can you data log?

http://www.amazon.com/BAFX-Products-Bluetooth-diagnostics-Android/dp/B005NLQAHS

that and the free program FORScan on a laptop with bluetooth can do some sweet stuff. it also works with torque on android phones.

 

[Mechanicboy]

The Dr. Tranny (Friction modifier) suggestion was more of a "put it in and see if that's the issue" type of thing before you flush her out with V. I however have been running it for years without the shudder returning. Since yours is happening at all speeds I honestly don't think that's the problem.

I'm referring to the motor. If it were me I'd start with plugs and wires. Some of the gen1 guys might be more familiar with said issue so I'd wait for some of their opinions.

Gotcha.

dexron/mercon shouldn't be used, mercon v should.
dr tranny helps some people, but this doesn't really sound like a trans issue.

plugs and wires been changed recently?
autolite 764 plugs gapped to .050-.054, and ford wires work fine, and are not terribly expensive.

any codes? can you data log?

http://www.amazon.com/BAFX-Products-Bluetooth-diagnostics-Android/dp/B005NLQAHS

that and the free program FORScan on a laptop with bluetooth can do some sweet stuff. it also works with torque on android phones.

I did not change the plugs but I did check them and check their gaps not very long ago and they were good, no funny colors/buildups either. I do most of my work on diesels these days so I get a little rusty on gas stuff. I didn't ohm check the wires though, so I'll do that.

I have a OBDii bluetooth scanner I use with torque Pro on my phone. I can datalog with it, let me know what you want and I'll go for a drive.

 

[chris2523]

mostly interested that the O2s are switching quickly, and that they match left to right.
helps rule out vacuum leaks or a lazy O2 sensor.

i'd maybe unplug the DPFE, as they can cause some driveability trouble when they go bad.

check for dead spots in the TPS voltage curve, that the maf readings look relevant, maybe even unplug the maf too temporarily to see what happens.

i dunno, not super sure without just having the car in front of me. trying to think of what might cause a booming/rattle sound. thats new to me.

doesn't really sound like low pressure, but its worth a check if you have a gauge handy.