help... running rough/ idling problem suggestions?

Aquino(FR) · #1 (**permalink**) 03-28-2008, 09:13 PM

I recently replaced the sparkplugs/wires/cap and rotor and igniton coil on my 91 164s and the car still seems to run rough. To be more specific, the car runs rough and when the car is warmed up it starts to idle high like around 1500-2000. On numerous occasions, I would have to rev the engine a couple of times before it idles normal again. The car is still at the mechanic shop and he still has to diagnose it. He said that he will do a fuel pressure test and then do a compression test in making sure the engine is ok. The reason behind the compression test is because it almost seems like its running on 5 cylinders but we could be totally wrong..

He also indicated that it could be the O2 sensor. In otherwords, process of elimination at this point to determine the problem.

Is their any additional information I can pass on to the mechainc that will further help him pin pointing the problem??

He also noted which I have heard as well that once the car is warm you hear a knocking like sound in the car. I thought it was the tappets but he thinks it may be a piston?

Any suggestions would be greatly appreciated!!

**AlfaTango1** · #2 (**permalink**) 03-28-2008, 09:19 PM

Was it running like this before?

jol · #3 (**permalink**) 03-28-2008, 09:19 PM

Check that the timing belt hasn't slipped or vacuum leaks

Aquino(FR) · #4 (**permalink**) 03-28-2008, 09:25 PM

These symptons started about a couple of months ago... The mechainc did not mention the timimg belt but I will ask him.

What would be the best method at checking for vaccum leaks for this car?

oz3litre · #5 (**permalink**) 03-28-2008, 09:59 PM

Quote:

Originally Posted by Aquino(FR)

He also noted which I have heard as well that once the car is warm you hear a knocking like sound in the car. I thought it was the tappets but he thinks it may be a piston?

Any suggestions would be greatly appreciated!!

jontg428 · #6 (**permalink**) 03-29-2008, 12:37 AM

I believe the knocking is just piston slap, nothing to worry about

Aquino(FR) · #7 (**permalink**) 03-29-2008, 08:55 AM

He replaced the fuel pump not too long ago but from past threads Ive read that good fuel pressure is 48psi but what is good compression? I will find out from the mechanic today what these are..