Chevy & GMC Vans

GEJ,no more than normal water....You can use regular water, I just put the soap in just to help find the leak...

I can't believe nobody's mentioned motor mounts yet! It is possible that the engine is actually idling normally but the mounts are just worn out and allowing it to move around to much. That was the case with my van a few years ago.

i think i might have figured it out when in open loop it idles pretty smooth but it only happends in closed loop is when the rough idle happends could this be the temp. sensor the one for computer?

very well could be the temp sensor. If it's returning bad data to the pcm when it goes into closed loop, it'll mess up the air fuel mix. when in open loop, the fuel mix is controlled to a set program, tends to be on the rich side.

yeah i think i am gonna have to check that cause it also idles kinda low when in closed loop

other thoughts: idle air control valve port might need to be cleaned. What shape is your air filter in?

new air filter

okay here is what am been learning when the engine is in open loop it seems to idle a little high but when in closed loop it idles too low my throughts are could it be my coolant temp. sensor for the computer, cat. converter, o2 sensor or what else?

also what temp. does the computer go into closed loop and how would it know?

when my van goes in to closed loop which is at 150 -160 degrees then this is when it idles rough it only happends in closed loop. so what sensor could cause this it is a low idle does not stall seems to run lean sounds like it is kinda of loading up a little not that bad

any luck with this yet?
I don't have a silver bullet for you to fix the low idle problem based on the thread so far, but I spent a lot of time bringing my '89 back from the brink of death. I'm certainly willing to share the things that have improved the way my 4.3 runs the most. PM me if you like. I check the site almost every day.

Kings-x59 pm sent!!

UPDATE:I got a tach install it is a super tach2 okay when the computer goes into closed loop which is arould 140degrees to160degrees the engine idles at 350-400rpm in gear it does not stall it just idles low like that it does not fluxturate it is stable but it shakes but the engine stays running very strong what could be the issue? it only happens in closed loop and off idle it is perfect and when in open loop it idles real smooth at 750-950rpm stable.

bump please help!!

On my Stro I was having idle problems, Would start running crappy intermittently, including on the expressway. after loosing the other half of my hair, A buddy of mine had me go to his shop on his off day and hooked it into their analyser.

Come to find out that the shop I had replace my O2 sensor a year ago didn't put the little boot back on and the connection was a little corroded.