M103 RPM Hunting
 

What would cause the RPM to fluctuate between 350 and 600 when in Drive or Reverse and your foot is off the brake pedal with the car moving under idle?

A dirty MAF sensor can do that.

agreed....but there is no maf on that engine.

you sort of know the drill...it's almost always some sort of vacuum leak.

gah! vacuum leak?! I have combed through those lines about 4 times in the last 3 weeks. This car... I tell you.... :mad:

ok....do you have a spare ovp...or can you get one from the junkyard?

I could send you a single fuse one if that would work...

Any fuel smell? I have a similar problem but I'm pretty sure its a slow fuel leak as it stinks after sitting for 10-15min. It doesn't drop at all while in gear but at a stop (like at stoplights)?

I swapped my 2 year old twin fuse OVP with a single fuse spare from a junk yard, no change in engine behavior... really appreciate that offer though. :)

I will have to double check for this tomorrow morning or late this afternoon if I get some extra free time.

Thanks for the suggestion, I will report back ASAP.

Also check the rubber boot that connects the air valve assembly and the throttle body as it cracks with age.

also the little rubber hose that connects from the valve cover gasket to the ??? it's about 2 inches long....gets very hard and cracks....

spray the hose connecttions at the icv with brake parts cleaner or wd 40...see if that does anything.

ICV
 

ICV: A Thorough cleaning will do the trick ,if its gummed up at the moving plate it moves erraticly and causes the fluctuating idle.