Hey all,

My 92 has developed a seemingly low idle here recently. It used to idle at around 500 RPMs (700-750 w/ AC compressor load), however now without the A/C compressor on, it idles at 250 RPMs (the first tick mark). The only vibration I noticed at first was in the gear shift (5 spd.), however now it sometimes shakes the entire truck. When A/C compressor kicks on, it goes right back to the 700s. I know there's a screw on the top of the engine I can turn, but is this just a temp. fix or is there something else going on here?

Thanks for any input.

 

Your first thought should be to look at your throttle body, it's probably very nasty.
Which motor do you have?

 

It's the 3.0 V6. Should I go ahead and turn the screw to tweak the idle or should I just deal with it until I can clean the throttle body? BTW- Where is it located and how would I clean it if I had to?

 

Click ME for a TB cleaning page.

 

Thanks! I will definately give that a try and see what happens.

 

This can also be caused by dirty or improperly gapped spark plugs. Dirty air filter, warn out distributer cap or rotor, etc.

 

Maybe this will help narrow it down some...the truck is now dying anytime I put in the clutch (or allow it to sit idle anytime when it's warm. BTW- Temp. gauge shows normal.

 

Is your check engine light on? If so check the codes, if not there are several areas to look into! If you notice signs of mixture problems (rich/lean) then perhaps the MAF (mass air flow sensor)... Easy to test with an ohm meter and a little breath. There is a possibility that you have a vacuum leak and you are not actuating your throttle plate vacuum motor (which keeps the car idling at its predetermined speed. Also there will be a throttle plate position sensor that may be a contributing factor! Once again check the trouble codes, if the problem is electrical then the car will tell you what is wrong. I had a similar problem on a 91 Land Cruiser and was able to fix it by cleaning the IAC (idle air control valve)!!! Let us know what the check engine light reads. To throw one more on the pile a pluged fuel filter can kill an engine, although normally at speed, not at idle!

travis

 

Hmmm...no check engine light, although I wish it was on, as it would help alot as to the problem. The truck dies now any time it is in neutral, even when I first start it up. This has just recently started happening (as of yesterday), and I filled up just the other day as well. I'm beginning to think I have a bad tank of gas. Would that cause this problem? BTW- Truck works wonderfully in gear and on the highway, only when I pull it out of gear does it stop (and the engine will die if you pull it out of gear while on the highway).

On a side note, the only thing that will keep the engine going when in neutral is either giving it a little throttle or when the A/C compressor kicks on. I've tried turning the screw a little bit (don't know how sensitive it is), but no avail.