Ive got a customer 04 GMC sierra 3500 6.0L and have replaced sensors the scanner said were bad and it still runs bad. I noticed it kept blanking out tyhe screen on my scanner. How di I check if the ECM is OK?
04 GMC 3500 Sierra 6 litre engine running badly at idle it misses terribly.
Under load driving, it has no power AND RUNS BAD MISSING. REVING IT
UP WITH NO LOAD IT SOUNDS GOOD. tHE CODE READER SAID THE AIR
FLOW WHICH I REPLACED. THEN THE MAP SENSOR CODE, SO I
REPLACED THAT. THE MAP SENSOR CODE IS BACK AND SO IS THE AIR
FLOW CODE AND I NOTICED THE SCREEN KEPT GOING BLANK ON MY
SCANNER, IM THINKING ECM, BUT HOW DO I TEST FOR THAT
First, I would try a different scanner. Maybe check one easy to reach sparkplug to determine how bad the other ones are. Then check the air and fuel filters, and any new codes coming up.