Hi every body... I just wanted to introduce myself and ask a few questions.
I recently traded a old jeep i had for my 98 Yukon. I traded with the knowledge that the yukon had a few problems, but they seemed easily fixable and a good deal... well 3 weeks later i am still having issues with it, so i figured i would bring my issues here and see if y'all couldn't help me out.
Here's the issues i have come up with and fixes i have done so far.
Cyl 4 misfire - replaced plugs and the whole distributor
Low compression in cly 4 (result of bad distributor and carbon build up?). Ran sea foam through intake and oil pan, techron in fuel.
sometimes has no power and an intake backfire when trying to accelerate - inspected valve springs, they all looked good.
So what i am dealing with at this point is the yukon will run great one day, and terribly the next. It seems to cycle between a hard misfire at idle with decent power all the way through the rpm. Then it will idle fairly smooth with no power through the rpm and it will backfire through the intake if i keep my foot in it. Then it will run like it should as far as power, but have a rough idle.
Also today a new issue has popped up with the whole electrical system going dead after i turn it off and then when it comes back on (few seconds later) the clock is reset but not radio presets, SES is off, and the motor doesn't want to idle initially (like the batter was unhooked). Only codes i'm getting is an occasional cyl 4 misfire and a rich/lean code on the right side's o2 sensor. Finally the oil is staying clean, no coolant or fuel is in it, and exhaust does not smoke or smell like coolant.
So what does this sound like to you? PCM going bad maybe or just extreme carbon build up?
Thanks for your help!
I recently traded a old jeep i had for my 98 Yukon. I traded with the knowledge that the yukon had a few problems, but they seemed easily fixable and a good deal... well 3 weeks later i am still having issues with it, so i figured i would bring my issues here and see if y'all couldn't help me out.
Here's the issues i have come up with and fixes i have done so far.
Cyl 4 misfire - replaced plugs and the whole distributor
Low compression in cly 4 (result of bad distributor and carbon build up?). Ran sea foam through intake and oil pan, techron in fuel.
sometimes has no power and an intake backfire when trying to accelerate - inspected valve springs, they all looked good.
So what i am dealing with at this point is the yukon will run great one day, and terribly the next. It seems to cycle between a hard misfire at idle with decent power all the way through the rpm. Then it will idle fairly smooth with no power through the rpm and it will backfire through the intake if i keep my foot in it. Then it will run like it should as far as power, but have a rough idle.
Also today a new issue has popped up with the whole electrical system going dead after i turn it off and then when it comes back on (few seconds later) the clock is reset but not radio presets, SES is off, and the motor doesn't want to idle initially (like the batter was unhooked). Only codes i'm getting is an occasional cyl 4 misfire and a rich/lean code on the right side's o2 sensor. Finally the oil is staying clean, no coolant or fuel is in it, and exhaust does not smoke or smell like coolant.
So what does this sound like to you? PCM going bad maybe or just extreme carbon build up?
Thanks for your help!
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