ISC RPM out of range
 

I am new here. I fear that my question has been asked and answered 1,000's of times, but I do not know where to go to look for the answer. Here goes: '93 Deville 4.9; will not idle consistently. Sometimes when it first starts, it will idle fine. After I drive it for a bit, it idles down to nothing and stalls the engine. I have cleared the codes. The only one I get is E30. What do I need to change to fix this issue?

Thanks, hope I am in the right place for this thread.

E030 is an ISC error code...the ecm has commanded the isc motor to make a correction in the idle speed and that action wasn't completed correctly.

a couple possibilities:

the ISC motors tend to wear out or get dirty and then the motor wouldn't run in and out properly...in fact, they might even get noisy...so if you hear a clunk noise when you turn the key off, that ISC motor (mounted on the side of the throttle body) is probably bad.

also possible is the distributor gears wearing and causing unstable idle which in turn would set the E30...if you were to remove the distributor and look at the drive gear, it's obvious that it's messed up...the teeth will be very thin.

don't go turning the plunger screw or the minimum idle speed screw as you will cause more problems




.

Is there anything other than noise that will give me an indication of whether the Idle speed control motor is bad?

How about installing the isc motor from my '95 deville to verify the problem?

Really don't want to spend the $70.00 on a new motor if not necessary, and not really up for a distrib removal either if there is something else I can do.

Thanx

You can, they are basically the same engine.

Thanks folks, new motor did the trick.