STRANGE PROBLEM? anyone for a ride?

About 3 months ago I bought myself a sweet 99 Crown Vic P71.
Everything seams to be in order beside one little thing.

Car when in Park/neutral creates slight vibration of chasis. Vibration is regular but not constant. vibrates-stops-vibrates-stops. Done this done that didn't help:

- fuel filter
- air filter
- new sparkplugs
- new sparkplug boots
- new PCV
- good fuel injector cleener [M3 brand]
- new engine and tranny mounts [needed replacing anyway]

Driving on the mid-grade or premium. Car has about 81K on the odo now ... don't think this is the reason :>

Guys, please ... any help, any suggestion maybe someone encountereed the same problem ... it just drives me nuts ...

Mike

try raising the idle a little bit

rising idle by acclerator pedal actually helps [ i've tried it before] still as far as I know PI's already have highie idle due to highier alternator output ... is that really the reason for those damn vibrations ... still waitng ... for opinions

Mike

i mean adjust the idle on the engine...tighten the throttle cable a little bit, my old car used to vibrate at idle until i raised it....then it went away.

First u dont have to run premium because the car is not set up for it, it is set up for 87 stock in the computer but it is up to u but if i were u i would run 87.

When these engines are running right you may have a really hard time hearing or feeling that they are running at all. It sounds to me like you might have a little vacuum leak causing it to run rough. It could be that the IAC Idle air control valve is getting a little flaky.

You can also try cleaning the MAF mass air flow meter with electronic parts cleaner, cleaning the throttle body with Throttle Body Cleaner and checking to make sure that the air intake connections are tight. also if that does not work try using some seafoam in the engine that stuff works mad good, Good luck.

It may sound stupid, but is your AC on? The AC does cycle, and can make a low RPM car shake a little.

Check your exhaust pipe mounts before and after cataly.converter. Check heat shield around transmission on exhaust pipes. Make sure A/C is off, the compressor sometimes makes this noise and can mask what realy is vibrating.....ALSO- on the police packages water will build up in the tail of the exhuast and will roll around until the pressure blows it out. The water getting rolled around by the pressure will sometimes bubble and make this noise. Try letting the car run and stand/kneel next to pipes look and listen, have freind rev the gas to blow water out if water comes out and noise stops then thats most likely it :naughty: