vibration

[Hnichols]

Hi everyone,
I'm going to try to describe my latest issue as best I can, hoping someone might offer some insight.

Car is running fine, and I am driving along Chicago's Lakeshore Drive in 2nd gear, at about 5k rpm for a couple of minutes, and then drop into third. Shortly thereafter I notice a subtle off and on "tugging" as the car is driving, as if the engine is missing -- but the engine seems to be running smoothly. If I gun the motor in neutral, I hear/feel a low frequency vibration between 1500 and 3000 rpm. It's all very subtle, and their are no odd noises (clunks or whining) coming from the drivetrain or the engine.

I know all that sounds kind of vague, but maybe someone has experienced something similar.

TIA!

[T77911S]

why don't people just put their flippin cars in their signature so we don't have to guess at what they are driving! this really gets frustrating.

[E Sully]

He has a 1988 listed in his garage part of signature.
Could be issue with worn contacts in AFM. There is a way to check AFM with 9V battery.
Pull spark plugs to see if they show good combustion. Check distributor cap, rotor, wires. Possible injector issue.
O2 sensor working?

[bickyd]

i also have an 88 carrera. I had somewhat the same issue. I removed the air flow meter; took it apart carefully, and re indexed the wiper arm. I also changed the fan to a new one and the stumble i had disappeared. my fan was 30 years old and had cracks in the fins. I also retourqued the intake plenum back to factory specs. it was noticeably loose.( half to three quarters of a turn on most bolts). those three issues made a big difference. hope this helps.

[Hnichols]

First of all, sorry about not having my car in the signature; just updated that.

Thanks for the replies. At some point I'm going to have to look at the AFM because I sometimes get bucking at >2000K when the engine is cold. It's always done that, and I haven't dealt with it yet because the car runs smoothly when warm, and, truth to tell, the bucking forces me to keep the revs down when it's cold, which isn't a bad thing.

Anyway, this issue is different. It's quite subtle, but it feels something is off. It feels like a drivetrain issue -- could it be clutch or motor mounts? Again, there are no squeals or clunks. but no popping or misfiring either.

[Lyle O]

I had a similar issue a while back, and discovered that my battery and spare tire were not properly secured/tightened down. While they were loose, a very minor frequency generated somewhere was amplified dramatically. It was always at the same RPMs, too. See the thread I started on this. Once I tightened these items down, all was golden (still is). May not be your issue, but it's worth a look-see...

Drive train vibration at 3300 RPM

[Hnichols]

Lyle: it's funny, I just read your thread on the archives (searching for "motor mounts"), and then I return here to see your post! It certainly won't hurt to check the spare, but I would be very surprised if that were the issue (of course, you were too ...).

[Stahler]

Originally Posted by T77911S

why don't people just put their flippin cars in their signature so we don't have to guess at what they are driving! this really gets frustrating.

Why don't people who are so easily frustrated just relax and stop posting arrogant comments?

[Trackrash]

I had exactly the same experience. Turns out I had not fully released the parking brake. Once warmed up I felt a vibration/ lack of power. Doohh

[Joe Bob]

Engine/transmission mounts or loose sway bar mounts are my WAG.

[T77911S]

Originally Posted by Stahler

Why don't people who are so easily frustrated just relax and stop posting arrogant comments?

when you have been around longer THEN you can give me advise.

to the OP,
my brother has a line on a 2002, supposedly has the flares on it. no engine.
pretty cheap I think.

[Hnichols]

Just drove the car again -- I think I was wrong that it might be a drivetrain issue: the engine is running a bit rough at idle up to about 3K. Used to be smooth running when warm, but that seems to be changing. Time to review posts on the AFM. ...

Funny, I just resolved a no-start issue -- cracked solder connections in the ignition circuit of the ECU. Just got that sorted out, now this.

Originally Posted by T77911S

my brother has a line on a 2002, supposedly has the flares on it. no engine.
pretty cheap I think.

With these it's all about rust (mechanicals are very robust and parts readily available). But your brother probably already knows that.