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I have a 1980 CJ7 jeep with a V8 automatic, an Edelbrock performance series intake manifold, 4bbl carburetor, MSD (brand new) distributor, coil & plug wires (same brand MSD). Changed my plugs, fuel filter & the air filter is fine.
My problem is that after the engine warms up, it starts to miss/sputter/run rough and eventually dies sometimes on me while at a stop, but will start right back up again just as if nothing was wrong, but continues with the same symptoms. It runs GREAT until the engine warms up. I have taken it to a very respectful mechanic here in town and he said I had a bad distributor, the new MSD I had just purchased. So I sent it back to the MSD tech dept and they checked it out and sent it back to me as OK. I put it back on the engine and the same symptoms returned when the engine warmed up again. I then replaced my carburetor (with the same kind; a 1406 4bbl Edelbrock performance series) instead of rebuilding it. I installed it today and the engine started right up. I took it for a test drive and never ran betterâ€¦until the engine warmed up again and the same symptoms returned. I rechecked the timing and was where it is supposed to be. There is no water in the oil nor does the coolant look bad. The distributor negative wire is connected directly to the battery per MSD tech people & the MSD coil is connected through a resister per the coil instructions. The manifold vacuum is at 13-15 psi. I checked the fuel pressure (I still have the stock mechanical fuel pump) & for my 304 itâ€™s supposed to be 4-6psi at idle & it is sitting right at 6psi. We tried to adjust the idle screw mixtures (with someone who is knowledgeable with carburetors) with no positive results. I am at my whitâ€™s end and really need to get my jeep running. I have had this jeep for 12 years and have never had ANY problems like this. I think I have told you all the information I can think of that I have done to try to fix my problem. I am going to replace the spark plugs and fuel filter again tomorrow (Sunday) but donâ€™t think itâ€™s going fix the missing/sputtering & rough running. Please help me:( Thank you in advance to everyone that tries to help me.
Cliff

Optional Information:
Pre-1981 Jeep CJ7 304 v8

Already Tried:
I have a 1980 CJ7 jeep with a V8 automatic, an Edelbrock performance series intake manifold, 4bbl carburetor, MSD (brand new) distributor, coil & plug wires (same brand MSD). Changed my plugs, fuel filter & the air filter is fine. My problem is that after the engine warms up, it starts to miss/sputter/run rough and eventually dies sometimes on me while at a stop, but will start right back up again just as if nothing was wrong, but continues with the same symptoms. It runs GREAT until the engine warms up. I have taken it to a very respectful mechanic here in town and he said I had a bad distributor, the new MSD I had just purchased. So I sent it back to the MSD tech dept and they checked it out and sent it back to me as OK. I put it back on the engine and the same symptoms returned when the engine warmed up again. I then replaced my carburetor (with the same kind; a 1406 4bbl Edelbrock performance series) instead of rebuilding it. I installed it today and the engine started right up. I took it for a test drive and never ran better¡Kuntil the engine warmed up again and the same symptoms returned. I rechecked the timing and was where it is supposed to be. There is no water in the oil nor does the coolant look bad. The distributor negative wire is connected directly to the battery per MSD tech people & the MSD coil is connected through a resister per the coil instructions. The manifold vacuum is at 13-15 psi. I checked the fuel pressure (I still have the stock mechanical fuel pump) & for my 304 it¡¦s supposed to be 4-6psi at idle & it is sitting right at 6psi. We tried to adjust the idle screw mixtures (with someone who is knowledgeable with carburetors) with no positive results. I am at my whit¡¦s end and really need to get my jeep running. I have had this jeep for 12 years and have never had ANY problems like this. I think I have told you all the information I can think of that I have done to try to fix my problem. I am going to replace the spark plugs and fuel filter again tomorrow (Sunday) but don¡¦t think it¡¦s going fix the missing/sputtering & rough running. Please help meƒ¼ Thank you in advance to everyone that tries to help me. Cliff

Customer (name blocked for privacy)

Status: Closed Value: $30

Did the vehicle ever run acceptably at normal operating tempature with the combination of gear you mentioned or did it start acting up when you put all of the gear on?

Does the carb have a electric or mechanical choke?

Oldbuzzard
I hope this answer is acceptable. It has been a pleasure answering your question.

Reply to Ed Liss's Post: I first put my 4bbl & intake on the engine about 7 years ago and ran perfect for those years. It just started acting up one day and took it to that same mech mentioned above and he replaced a "pickup" in the old stock dist.I had on it but it didn't work out very well so instead taking it back I just replaced the distributor/coil/8.5 plug wires-all MSD by my choice. Still didn't work after that, so I thought it could've been something with the carb so I replaced with same one. Thank you by the way. Cliff

Have you checked all of the vacuum lines/hoses for air leaks? Did you notice any changes in oil pressure? Have you checked your cylinder compressions?

Oldbuzzard
I hope this answer is acceptable. It has been a pleasure answering your question.

Reply to Ed Liss's Post: Yes, all vacuum lines were checked with the same psi results. There were no changes in my oil pressure. I haven't checked my cylinder compression yet. But I do have the tools to do that with. Would that really make that kind of difference only after the engine warms up to start missing and everything else?

I have a friend with an 84 jeep that has a piston ring problem which allows a lot of 'blow by' and loss of compression, which causes high oil pressure and rough running.

Does the vehicle have an pollution control system? EGR valve, PVC valve?

Oldbuzzard
I hope this answer is acceptable. It has been a pleasure answering your question.

Reply to Ed Liss's Post: I don't have an EGR but I do have a PCV valve that I did replace. My oil pressure is fine but does consume a lot of oil, has never smoked but has started to a little,not very noticable though. I'm still going to check the compression this Saturday. It wouldn't suprise me if my engine needs a rebuild or if that's the case, I'll put a 360 in it. I appreciate all these answer/questions so far and I think I know where it'll probably go eventually. Thanks Ed

Clif Meade

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