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7 Posts
Discussion Starter · #1 ·
Love my 09 2500HD Silverado w/ Allison, 110K miles bought it from a landscaper last May who didn't tow anything heavy with it and used it mostly freeway. I have been towing a heavy triple axle trailer with a 12,000# boat, and a small 5,000# travel trailer RV.

First trip from San Diego to Seattle with the boat I had a few MAF error messages after losing power in the Grapevine and Siskyous. CHECK ENGINE light with POWER IS REDUCED error message. Heavy load uphill I wasn't entirely surprised, and went away after a rest and unplugging and replugging in the MAF sensor.

In between these error light/messages the truck ran fine, towing like a champ and handling great with the heavy load and up and down hill, 1,300 miles.

After replacing the MAF and sensor back home, and re-flashing the computer, I continue to OCCASIONALLY get the engine light and MAF error codes towing the small RV trailer and OCCASIONALLY towing the boat. More recently I have had the check engine light with exhaust recalibration message. Again, in between these error messages the truck runs like a champ, and tows both units just fine for hundreds of miles up and down and around.

This past week, towing NOTHING, cruise control set at 70 going over a relatively gentle mountain pass, I had the CHECK ENGINE LIGHT and EXHAUST CALIBRATION message with MAF codes. This has me bothered, as this truck should NOT have these codes and I should not receive exhaust calibration messages or reduced power up a gentle mountain pass WHILE TOWING NOTHING.

My mechanic and I are stumped, and I'd like to turn to this forum for advice before we start tearing apart the turbos and aftercoolers etc....

To recap: Infrequent check engine light with reduced power error message and MAF code towing big and medium sized stuff uphill. Also infrequent check engine light with reduced power error message and exhaust recalibration error towing big and small stuff on flat, AND... NOT towing anything up a gentle slope mountain pass. We have replaced the MAF, the sensor, the MAF sensor pigtail, re-flashed the computer. I've been super proactive on all maintenance since I bought the truck used 9 months ago from a landscaper who didn't tow anything heavy ever. 110,000 miles.

Any ideas?:help :D
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