Strange idle issue
 

Ok here goes..

I have a 2000 s series vin #8 single cam 5 speed

I have been trying to figure out this idle issue for some time..

It idles at 750 all the time but has a miss and a light popping sound from exhaust only when idling...

Car runs great from idle pleanty of pickup and no hesitations hiway speed easily 90+ with no studder and in city no hesitation from lights or stops..Car starts right up every time ...All is good but the idle...

heres what i have done so far


replaced the temp sensor
replaced plugs and wires
checked compression all even at 180 give or take 1 or 2
replaced egr
checked leak down there was no sounds and no drop
replaced iac and cleaned throtle body and as much of the intake as possible
checked the injectors (pulled each one while running one after another and there was a change on each)
used a stethascope to listen to injectors they all sounded the same

and also used stethescope to listen to spark with engine running spark sounded steady in each...

checked spark at each cylinder with spark tester it was great on each..

used a snapon scanner no codes

only thing noticed was map sensor reading low vacumme at idle only around 8

did a vacumme leak test found none

usually if there was a vacumme leak it would hi idle mine never does it stays solid 750 ..

well there it is i am stumped now dont know what else to do
if anyone has any ideas i would really like to hear them

I would appreciate all the help i could get thanks

jerry

Jerry ............... did you replace the ETCS connector?

does the car have a fast paced vibration at idle?

Sounds like a bad valve to me. Try running a can of Seafoam through the engine before your next oil change.