88 3.9 runs rough
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Joined: Jan 2009
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From: Duncan SC
88 3.9 runs rough
First post here, but I have been browsing since I have been working on the truck. I've read the FAQ and done a few searches.
Here's the problem:
Truck is cold- cranks and runs fine until warms up. Once it warms up, the idle changes and it begins to run rough. It gets a skip/miss to it. When I take it out of park to go in drive or reverse, it gets worse. When driving it is underpowered and has a delay between pushing the gas and actually going. This is extremely bad when climbing a hill. I can hear the rpm's but it has no go (no tach in the 88). Also after driving a while, the oil pressure will drop when coming to a stop and the low oil light will come on. When this happens, it sounds like it is about to die. To prevent this, I have to keep a foot on the gas and one on the brake.
Here is what I have done:
Basic tune up things like oil change, belts and hoses, fuel filter, plugs, wires, cap and rotor, pcv, cleaned throttle body and idle air valve, and air filter. I checked codes and only got a code 12, which I believe is normal.
I just got this truck from my dad and it only has 60,000 miles on it. Other than this issue, it is in pretty good condition. Sorry for the long post. Any input is appreciated. Thanks,
Chris
Here's the problem:
Truck is cold- cranks and runs fine until warms up. Once it warms up, the idle changes and it begins to run rough. It gets a skip/miss to it. When I take it out of park to go in drive or reverse, it gets worse. When driving it is underpowered and has a delay between pushing the gas and actually going. This is extremely bad when climbing a hill. I can hear the rpm's but it has no go (no tach in the 88). Also after driving a while, the oil pressure will drop when coming to a stop and the low oil light will come on. When this happens, it sounds like it is about to die. To prevent this, I have to keep a foot on the gas and one on the brake.
Here is what I have done:
Basic tune up things like oil change, belts and hoses, fuel filter, plugs, wires, cap and rotor, pcv, cleaned throttle body and idle air valve, and air filter. I checked codes and only got a code 12, which I believe is normal.
I just got this truck from my dad and it only has 60,000 miles on it. Other than this issue, it is in pretty good condition. Sorry for the long post. Any input is appreciated. Thanks,
Chris
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Joined: Sep 2006
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I would include temp sensor. i changed the temp sensor in my 90 years ago, it was a Auto Zone one ran ok for a few days and then started doing what you are posting. I ended up taking it to the dealde and it was the stupid Auto Zone sensor. When it comes to sensors use factory parts.