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Ask GM Tech (Cam) Your Own Question
GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29427
Experience:  GM Grand Master Technician 2007. 14 years experience.
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1999 chevy suburban: trouble code..Mass..shifts..under acceleration

Customer Question

I have a 1999 chevy suburban that is showing trouble code P0102 Mass or volume air circuit low. The truck is also shifts very hard when not under acceleration. Are the two items related and how do I fix the problem?
Submitted: 7 years ago.
Category: Chevy
Expert:  GM Tech (Cam) replied 7 years ago.
Welcome! Are you running an aftermarket oiled filter?
Customer: replied 7 years ago.
Yes.
Expert:  GM Tech (Cam) replied 7 years ago.
OK, that is your issue. The oil from the filter is coating the sensor, making it read false engine load and air flow, which causes the shifting issue. I would take your filter out, clean it and use as little oil as possible, then take your mass air flow sensor and clean it with carb cleaner.
Customer: replied 7 years ago.

Sorry I miss read your first question. I thought you asked about my oil filter. I am not using an oiled air filter.

If it matters when I read the trouble codes I had 2 or 3 others but when I cleared them they all went away except the p0102. Also, I don't drive the truck much so it sits for weeks at a time.

Expert:  GM Tech (Cam) replied 7 years ago.
OK, clean the sensor anyway. It is likely dirty.
GM Tech (Cam) and 5 other Chevy Specialists are ready to help you
Customer: replied 7 years ago.
So I just got done cleaning the sensor and I am still getting the sme trouble codes and the same shifting problem. I am willing to replace the sensor but they are $200 so I would want to be sure that was the problem.
Expert:  GM Tech (Cam) replied 7 years ago.

Lets look at a couple of other things first. This is the 5.7L engine? Does the idle seem different?

Customer: replied 7 years ago.
yes, it seems to pulsate
Expert:  GM Tech (Cam) replied 7 years ago.
OK, I would unhook the MAP sensor first. It and the throttle position sensor are used in the monitoring of the MAF, and if one is low, it can call the MAF Faulty.

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