Wild idle on my 92 mtx...

[Brandontw]

My Sho doesnt run to good to begin with, but i think the worst problem is that when I take it out of gear and start to coast with the clutch in, or at a stop light in nuetral, my idle goes wild. My RPM's drops down to almost zero and then jumps back up past 1500 then settles back down to about 950 then hops up then drops down..there isnt any pattern to it- its just random, and somtimes it drops all the way to 0 and I have to restart the car. Is there an idle sensor or something easy I can replace? What is its deal?

 

[SeanMc]

I'd put money on the idle control valve. Even if you don't have a CEL, you should still check your codes.

 

[Brandontw]

well i tried pulling my codes with the paper clip jumper and the flashing CEL and i got some crazy stuff:

117-ECT sensor
217-primary cuircuit failure-coil 3
652-TCC cuicuit fault
817-????
658-????
528-????

 

[pete315]

I had similiar problem. change idle control valve. took 5 minutes to change. idles great now. had same problem in mom's 89 Towncar.