'94 ST Idling Seems Very Low, Symptoms noticed after long hibernation period Options

[UTSlickVic]

Hey all,

Hate to say this but I had not started/ran my car for 6+months. So I decided to get her started and do some maintenance. Before I started her I changed the oil and filter. Had to jump her to get here started, but after that all was fine (battery practically brand new). It has a very small amount of fuel left but did not fill her up with new fuel yet.

Ok, so here is what I noticed. Driving experience was great aside from the brake pad noise. She did not sputter nor was there a hesitation in acceleration (1.8L so I don't expect much). One thing that I that took me off guard was when I stoppped (still in drive) her idle was so soft/quiet that I tought the engine was about to die. 3Years Back: I got my timing belt changed and I noticed afterwards that it had a slight vibration when stopped / in park, but it never really phased me. Vibration can be "seen" through the steering wheel. Back to the Present: So I just chalked up the restart experience to me not being use to my 1.8L. So I got out left her running / in park, thats when I noticed I could see vibration (moderate shaking) on my trunk lid. Traced it back to the exhaust which then I traced back to the engine... which makes sense.

Long story short: The idle is so low that it is causing an engine vibration. Its like it has found harmony between idle and nearly koncking out. Right now she is idling at ~500-600 rpm.

Fuel filter has been replaced before (~3yrs ago) and PCV valve. As far as I know my throttle adjucstment has never been tampered with. After all this brain storming I regapped/cleaning up my spark plugs... made a very slight difference.

My biggest worry is ?maybe? my timing belt job was done improperly. Again I think she has HAD this problem ever since that time belt job... I think. But everyone tells me its not that (not sure why it can't be that). My distributer and and plug wire have never been replaced. I wish I can see a change in RPMs due to the a/c compressor but my a/c has been out of service for awhile now. Engine mounts need replacing?

I would like to know what I can do myself before I take it to a mechanic. Would like to here someone's diagnosis on this?

THANKS

-Vic

PS: Glad to be back on the 6GC board!

This post has been edited by UTSlickVic: Sep 7, 2010 - 4:41 PM

[SupraKid]

You can adjust the idle at the throttle body, there are 2 bolts, just adjust them and it physically moves the throttle cable,this will allow you to raise the idle. The shuddering may be because of the low idle. Adjust the bolts and get it idling around 700-900 and then see if its still shuttering. Is it misfiring?If so id tune it up,(oil,plugs,caps,wires,ect) If its NOT misfiring then id take a look at eh motor mounts, as rubber degrades after time..

[UTSlickVic]

You can adjust the idle at the throttle body, there are 2 bolts, just adjust them and it physically moves the throttle cable, this will allow you to raise the idle. The shuddering may be because of the low idle. Adjust the bolts and get it idling around 700-900 and then see if its still shuttering. Is it misfiring?If so id tune it up,(oil,plugs,caps,wires,ect) If its NOT misfiring then id take a look at eh motor mounts, as rubber degrades after time..

Yep I think the low idle is causing the vibration. I agree with you about the replacement of anything that can cause a misfires. I guess I will replace the plugs/plug wires and distributor before I adjust anything. To tell you the truth I don't want to mess with the throttle body wire.... yet. I guess I feel like it has nver been mess3ed with beofre, why should I start now. I will get my mechanic to replace the engine mounts, but after that, if nothing has changed then I will start to worry.

Wonder how difficult it is to replace the distrubutor cap?... new territory for me.

Thanks for your advice. Any others?