Last post on Aug 04, 2012 at 8:43 AM
You are in the GMC Jimmy
What is this discussion about?
GMC Jimmy, SUV
#19 of 79 Re: 1997 Jimmy chugs than sputters, and loses power going uphill only [daylyn]
Apr 17, 2007 (7:15 am)
Thats a hard code to clear sometimes as like 8 possible causes. Have you changed the plug wires? At night spray a fine mist on the boots and see if they arc. Then the coil could be failing so a load results in a weak spark. The crank sensor can be intermittant as it starts to go (under block and the pulses tell the PCM the crank position). Then the ign IC on the coil heat sink (not common). Or fuel pressure low so lean mixture results - again check pressure at fuel rail. Injection system problems also can cause.
#20 of 79 Re: 1997 Jimmy chugs than sputters, and loses power going uphill only [repairdog]
Apr 18, 2007 (7:25 am)
Plugs and wires were replaced. We're wondering if maybe it's the MAF sensor.
How would I find out if the coil was failing? Just replace it?
It seems that the truck only behaves this way on one hill, which is at a high altitude. If the MAF sensor was malfunctioning, would it cause the truck to behave this way in high altitudes?
Any way of knowing if the MAF or MAP sensors are malfunctioning before spending money to replace? I did lightly clean the MAF last nite, and made it up the hill a little further before truck crapped out......
#21 of 79 Re: 1997 Jimmy chugs than sputters, and loses power going uphill only [daylyn]
Apr 18, 2007 (9:05 am)
Dirty MAF does effect the mileage as runs richer so possible - clean with MAF, brake, or electronic cleaner but not carb (leaves residue).
Have to test the primary and secondary windings and some auto stores can test for you free.
#22 of 79 Re: 1997 Jimmy chugs than sputters, and loses power RESOLVED
Jun 29, 2007 (12:04 pm)
Just wanted to update all on what we finally figured out with this problem.
We replaced every "suspect" part on the damn truck, as follows:
Transmission (needed to be done, was slipping badly)
Cap & Rotor
Spark plugs & wires
O2 Sensors, MAF sensor, MAP sensor, cam position sensor, ignition control module sensor.
Intake manifold gasket
Fuel filter, fuel pump
Oil filter, air filter
And the problem was that the exhaust valves were burned. One exhaust valve had gotten sooo hot, that it was misshapen, and actually was thinning out.
Eventually, the thing got so warped, that the piston came in contact with it, and I lost all compression in that cylinder. This is the only way we would have ever guessed that this was the issue. The valves cost $35.00 each. Lots of labour - 8 hours, but the end result was a fix of $1300. Which is less than 1/4 the amount of money we spent trying to fix the damn thing.
We researched this issue for months and months. We never had anyone even guess that it might be exhaust valves. The only issue we had was high emmissions, and a random cylinder misfire code, which was intermittent (P0300).
Hope this information helps someone else out.
For additional info or input, feel free to send me an e-mail: daylynbchotmail.com
#23 of 79 Re: 1997 Jimmy chugs than sputters, and loses power RESOLVED [daylyn]
by Stever@Edmunds HOST
Jun 29, 2007 (12:12 pm)
Hopefully you'll be good for another ten years now that you have all those new parts on it. Thanks for the report!
#24 of 79 Re: 1997 Jimmy chugs than sputters, and loses power RESOLVED [daylyn]
Jul 01, 2007 (5:49 am)
If you would of had it hooked up to a shop's computer diagnostic machine it would have let you know that the cylinder wasn't firing, yes? Sounds like you wasted a ton of money on stuff that was not broke.
#25 of 79 Re: 1997 Jimmy chugs than sputters, and loses power RESOLVED [mtrotter70]
Jul 04, 2007 (8:11 am)
That's the problem. I had two seperate compression tests done at two seperate shops that were both showing compression in all cylinders.
Not until the valve actually warped and burned, did we find out that was the problem.
The original problem was the valve getting too hot.
#26 of 79 2000 Jimmy wont accelerate
Jul 11, 2007 (10:29 am)
#27 of 79 2000 Jimmy wont accelerate
Jul 11, 2007 (10:29 am)
Have a 2000 Jimmy, 114,000 miles. When taking off after starting vehicle, get tach around 2grand and while pushing accelerator the vehicle wont accelerate. Can push to the floor but nothing, tach will stay steady. Does not miss, bog down, nothing else unusual. After a couple of seconds it will take off. Is now at GM shop but they 2 hours in it and cant find anything. No codes, fuel pressure good, checked cap and rotor, nothing wrong can be found. He did say that in park and while pushing accelerator it doesnt seem like it picks up the RPMs like it should.
#28 of 79 Jimmy Misfiring
Jul 13, 2007 (2:53 pm)