Sounds like missing a cylinder above 60 MPH?

[codfizzle]

So I'm in the middle of a road trip, and I noticed yesterday that as soon as my car gets up to about 55-60 MPHs It gets this shudder to it, and it almost feels like when I get to this speed, one of the cylinders is skipping or something.
When I'm at a standstill, it idles fine with all cylinders. When I'm at a standstill and I rev the engine up to cruising RPM level (which is about 3200 when I'm doing about 80 MPH in 5th), It runs great with all cylinders.

It's only when I'm actually moving and get above 55 that the shudder happens, which would lead me to believe that it's a drive train problem rather than an engine problem, but this condition does seem to be having a slight effect on the engine. It does sort of act like it's missing a cylinder, especially when I'm climbing a hill. It has a decrease in power (not so much so that I have to shift down to 4th, but noticable nonetheless), and for some reason, the shudder just feels like it's coming from the engine, but I just can't tell for sure.

Has anyone experienced any of these symptoms during highway driving? I am leaving to go back home tomorrow afternoon, so any advice before then would be greatly appreciated, as I would like to solve the problem before I head out on the road again tomorrow.

Thanks in advance!

[codfizzle]

All right, nevermind. Found the problem. #3 plug was not seated in the hole, due to the crush washer jamming itself on the plug threads at an angle. Went to change the plugs, and that one was barely hand tight. That's what the sound and shudder was: the #3 cylinder was hemorraging compression out of the spark plug hole at highway speed.

[atroby91]

I think i have a similar problem.. I'll have to give my plugs a check. I changed them in june or july and torqued em right but i'll just do a double check

[mvons]

What a great thread. We had a shudder when accelerating up a hill. Let off the gas, and it recovered. Keep the gas on and oh my the shudder got worse. It was never consistent except hill and on the freeway. I told hubby about this post and sure enough the plugs hadn't been changed for 50k miles. No problem now. I love these easy fixes. He was too busy filling the PSF awaiting his rack & pinion change, so he missed the routine stuff.

[mvons]

Just an update. We had the shudder again, but this time when I was a passenger and could listen. The car wasn't shifting down from 4th to 3rd. Thus the shudder as the engine was lagging. ATF very low and very bad leak now. Time to search on that problem.

[codfizzle]

All right, nevermind. Found the problem. #3 plug was not seated in the hole, due to the crush washer jamming itself on the plug threads at an angle. Went to change the plugs, and that one was barely hand tight. That's what the sound and shudder was: the #3 cylinder was hemorraging compression out of the spark plug hole at highway speed.

Here's an update on this situation:

While fixing the spark plug problem did seem to temporarily make the shudder go away, it came back- not because of spark plugs this time...

I looked under the car and saw that the boot on the passenger side inner tie rod end (where it connects to the rack) was torn away, and I could feel significant play when I would manually wiggle the wheel by hand. Then I looked under the driver's side- same exact thing- torn boot, tons of play. And the play isn't just in the tie rod ends, it's in the rack also. So, now I get to do a whole rack and pinion replacement (which comes with new inner tie rod ends, if you get the complete unit).

I think it'll be a pretty easy job, and I found a complete remanned r & p unit for about $140. I'll get a 4-way alignment done after the replacement too, since I have some camber happening which is wearing out the outside corner of my tires quicker than the inside.

I'll update after the job and tell how it went.



Oh yeah, I haven't been on the forum for a long time....good to see y'all!

[93forestpearl]

FYI, a failing O2 sensor can cause the ECU to run really rich and you have over-rich mis-fires. I fooled around with that for a few months.

[codfizzle]

FYI, a failing O2 sensor can cause the ECU to run really rich and you have over-rich mis-fires. I fooled around with that for a few months.

Thanks for the heads-up! The problem is definitely in the steering system, though. Definitely not an engine problem any more- she purrs like a kitten! But once again- thanks.