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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29572
Experience:  GM Grand Master Technician 2007. 14 years experience.
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Howdy Westpoint.

Customer Question

Howdy Westpoint.
Submitted: 1 year ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 1 year ago.

Hi there, I am Cam. Can you tell me what issues your having with your Suburban?

Customer: replied 1 year ago.
It is running very rich, and has a bit of a rough idle. It will occasionally surge while sitting at idle, as well.I have replaced the IAC, multiple times, as it continues to throw a CODE 36 (ISC actuator error) and since my truck, from my research does not have an ISC, but rather an IAC, I went from there.Every time I replace the IAC, it runs much better, and the idle smooths out a bit.I am totally stumped at this point
Expert:  GM Tech (Cam) replied 1 year ago.

How long does the new IAC work for when you install it?

Customer: replied 1 year ago.
2-3 days tops.
Same thing when I replace the EGR valve.
Expert:  GM Tech (Cam) replied 1 year ago.

Does it change if you tap on the housing of the ECM itself?

Customer: replied 1 year ago.
I haven't done anything with the ECM.
That is located behind the glove compartment, correct?
Expert:  GM Tech (Cam) replied 1 year ago.

yes, that is correct.

Customer: replied 1 year ago.
Shoot..... So we're looking at a possible bad ECM?
Expert:  GM Tech (Cam) replied 1 year ago.

Possibly yes. The fact it works after putting in the parts then it fails again, its likely. And those older ones are bad for issues. Tapping usually makes it fail quicker.

Customer: replied 1 year ago.
Is there anything else I can do to verify that besides tapping it?
Expert:  GM Tech (Cam) replied 1 year ago.

Check for wiring issues, rubbing and such like that around it, open the cover and make sure the MEMCAL inside is seated, make sure there is no corrosion and such.