1997 GMC Jimmy Sputters and Chugs going uphill only

DAYLYN

MEMBER
1997 GMC JIMMY

4.3 with 197,000 km. I had the tranny rebuilt in Dec. Had code 0300-multiple misfire. Replaced plugs, cap and rotor O2 sensor, catalytic converter. Fuel filter replaced as well. Truck runs fine on flat ground and small hills. No more engine codes, but.

Drive up a steep incline, truck will lose power than sputter, and chug hard. Wants to stall. If I leave it at an idle for a few minutes, idle will return to normal, but can't get it up the hill.
What's going on?

Tuesday, April 17th, 2007 AT 11:33 AM

2 Replies

2CARPRO JACK

MECHANIC
11,533 POSTS

No codes. Have the fuel pressure tested, could be a weak pump

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Tuesday, April 17th, 2007 AT 5:58 PM

DAYLYN

MEMBER
2 POSTS

We had the fuel pressure, pump and filter replaced. New parts all check out ok.

Wondering about the MAF sensor. Would the truck behave like this if the MAF sensor was malfunctioning. I did give it a quick clean, and still experienced the same problem.

Seems that this only happens on one hill, which is at a high altitude. Wonder if this has something to do with it?
Also, any idea how to test MAF and other sensors to see if they are ok before paying to replace?

Thanks.

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Wednesday, April 18th, 2007 AT 10:19 AM