1989 302 Engine Problems
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Joined: Jan 2005
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1989 302 Engine Problems
I have an 89 F 150 4x4 with a 302. Heres my problem. The motor runs really really rough if at all. My mechanic has tested all the sensors and has swapped almost every thing that you can imagine off of a running donor truck. When he installed new plugs it ran great for a few seconds at 1/4 throttle then when he let off it went back to running rough again. He pulled the plugs and number 7 & 8 fouled. Thinking that it might be injection he took the fuel rail off of the donor and installed new plugs. Same thing happend again. What do you all think?
Freshman User
Joined: Mar 2004
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From: St Louis, Mo
How did you first notice the problem? Were you working on the engine, driving it or starting from cold. You need to narrow this problem down between air, fuel and fire. Will it run okay if you feed it carburator cleaner or gasoline? I assume you are fuel injected. You have two fuel pumps. Once fuel is eliminated then you are down to plug wires, disrtibutor and igntion module. Unless you have slung a chain. Then you better check timing.
Elder User
Joined: Sep 2004
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Check the fuel pressure and make sure it isn't grossly too high.
Check the distributor cap and the routing of the wires for cylinders 7 and 8.
As an experiment, temporarily plug the PCV hose. The stock PCV dumps into the back of the plenum, which tends to adversely affect cylinder 7 and 8 by dumping all the oil and blowby into them.
Check the distributor cap and the routing of the wires for cylinders 7 and 8.
As an experiment, temporarily plug the PCV hose. The stock PCV dumps into the back of the plenum, which tends to adversely affect cylinder 7 and 8 by dumping all the oil and blowby into them.
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Joined: Jan 2003
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From: 3rd Rock
Originally Posted by mccrumclan
I have an 89 F 150 4x4 with a 302. Heres my problem. The motor runs really really rough if at all. My mechanic has tested all the sensors and has swapped almost every thing that you can imagine off of a running donor truck. When he installed new plugs it ran great for a few seconds at 1/4 throttle then when he let off it went back to running rough again. He pulled the plugs and number 7 & 8 fouled. Thinking that it might be injection he took the fuel rail off of the donor and installed new plugs. Same thing happend again. What do you all think?
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