Hey guys. So I bought a 90 cherokee with a 97 4.0l motor in it. When I bought the jeep this summer it idled low, but ran great, Then it came to a point about 2 months ago that it stalled a couple of times from the idle being so low, so I drove with the defrost fan on to bump the idle up. Now the idle got a bit worse, so i adjusted it (by putting a zap strap between where the throttle linkage rests and the throttle linkage itself. This made the jeep Idle great for a few days. Now it still idles good but will randomly drop almost to a stall and then quickly jump back up, but it only does this in drive, In park or neutral it idles fine.

What could be wrong?

 

IAC valve. The 97 has one to keep the idle at the correct point. Not sure if there would be anything to hook it to in a 90 model, though.

 

Ya when I pull thhe iac electrical connector the rpms go to 3000rpm.

To bad its 100 bux. Is there a way to test the iac? I don't wanna spend 100 bux on a new one and have it not fix the problem.

 

$100? Where?

Autozone lists the IAC for the 1990 at $59.99 Part# AC301

and the IAC for the 1997 (which I recently replaced in my 97) for $35.99 Part# AC320.

They do look physically different. Which intake manifold is on the truck the 90 or the 97?

 

Lordco out here quoted me $103, wich is retarded. Not sure what year the intake manifold is, is there a way to tell?

 

Bump

 

So I've put seafoam in the gas tank, new cap and rotor new air filter, new fuel filter, adjusted tps, cleaned iac, and put a plugged vac hose wich was laying next to the egr onto the egr. So far its been running good.