Running Rough
jeffklinville
03-12-2005, 01:14 PM
I need some advice.
I have a 2000 JGCL 4.0L and I loaned it out while I was away on business.
I got a call from my friend that I loaned the car to and she told me that the jeep had over-heated but not to worry it shut it self off to protect itself. Ha! I told her that I had never heard of a motor shutting it self off to protect itself and that she had locked it up.
when I returned from my trip I found that the oil pan was full of water and oil, so I pulled the head and replaced the head gasket (checked the head with a straight edge before putting it back together) I also put in some sealant to seal any cracks if any (motor purr). it ran great for about 30 miles then started to run very rough. I pulled the valve cover and found that my rockers and pivots were chewed up so i bought new ones. Started it up again and it ran fine untill I drove it then back to the same rough running. I decided the problem might be electrical so I took it to the jeep dealer and spent $220. for them to tell me it was a bent valve (we think). I had a rebuilt head sent out and installed it only to find the exact same problem, car runs great at idle (even for an hour) but as soon as you rev it a bit or drive it and the rpm's get over 2000 it runs like crap again. What can be the problem? could it be electrical, could it be a problem with the cam and cam berrings? I have seen that the oil pressure drops after it warms up at idle but returns to 40 as soon as you touch the pedal. I am going nuts over this! oh, I also replaced the coil/spark pack with a new from the dealer part. (no plug wires).
please give me some solid advice. I had autozone and the dealer check the trouble codes and only one came up, misfire #6 cylinder.Thanks alot.
I have a 2000 JGCL 4.0L and I loaned it out while I was away on business.
I got a call from my friend that I loaned the car to and she told me that the jeep had over-heated but not to worry it shut it self off to protect itself. Ha! I told her that I had never heard of a motor shutting it self off to protect itself and that she had locked it up.
when I returned from my trip I found that the oil pan was full of water and oil, so I pulled the head and replaced the head gasket (checked the head with a straight edge before putting it back together) I also put in some sealant to seal any cracks if any (motor purr). it ran great for about 30 miles then started to run very rough. I pulled the valve cover and found that my rockers and pivots were chewed up so i bought new ones. Started it up again and it ran fine untill I drove it then back to the same rough running. I decided the problem might be electrical so I took it to the jeep dealer and spent $220. for them to tell me it was a bent valve (we think). I had a rebuilt head sent out and installed it only to find the exact same problem, car runs great at idle (even for an hour) but as soon as you rev it a bit or drive it and the rpm's get over 2000 it runs like crap again. What can be the problem? could it be electrical, could it be a problem with the cam and cam berrings? I have seen that the oil pressure drops after it warms up at idle but returns to 40 as soon as you touch the pedal. I am going nuts over this! oh, I also replaced the coil/spark pack with a new from the dealer part. (no plug wires).
please give me some solid advice. I had autozone and the dealer check the trouble codes and only one came up, misfire #6 cylinder.Thanks alot.
ekmarsal
03-12-2005, 02:21 PM
Hm. That's a tough one. How low the oil pressure goes down?
I don't think it's an electrical problem though, but check the fuel delivery system, you never know, since you have that faulty code reading, but I doubt. There's a reason for the oil pressure to drop ( again I don't know how low ) and that could be the problem you looking for. Check the oil pump, I'd say too.
I don't think it's an electrical problem though, but check the fuel delivery system, you never know, since you have that faulty code reading, but I doubt. There's a reason for the oil pressure to drop ( again I don't know how low ) and that could be the problem you looking for. Check the oil pump, I'd say too.
jeffklinville
03-13-2005, 03:01 PM
Thanks for the advice. Here is another kicker, my buddy in Las Vegas drove the Jeep to His friend @ Pep-Boys and Piper(the mechanic) just walked up to the Jeep and it stsrted purring like a kitten. He said to check out the MAP sensor. I will just keep checkin out everything I can think of. The oil pressure drops by about 60 to 70%. Thanks again for the advice and let me know if you think of anything else.
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