302 Missing at constant speed
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Junior User
Joined: Aug 2003
Posts: 72
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302 Missing at constant speed
1996 F-150 302 94,xxx
Runs fine on acceleration and idle, but at a constant speed the engine misses. Have tried new plugs, wires, cap, rotor. Got a new fuel filter today to try.
Any ideas?
Carrot
Runs fine on acceleration and idle, but at a constant speed the engine misses. Have tried new plugs, wires, cap, rotor. Got a new fuel filter today to try.
Any ideas?
Carrot
Fleet Mechanic
Joined: Aug 2000
Posts: 1,504
Likes: 1
From: Texas
Have you cleaned your IAB (Intake Air Bypass) valve on the body? If nothing else, have your exhaust system checked. Mine did the exact same thing, and it turned out to be a plugged catalytic converter (easy test, have someone rev the gas, while you put your hand over the exhaust pipe. If your hand isn't pushed away with a deal of force, and you don't feel a lot of pressure on your hand, then you've probably got a plugged converter.)
I hate chasing gremlins like that as much as anyone else.
Kyle
I hate chasing gremlins like that as much as anyone else.
Kyle
Senior User
Joined: Apr 2004
Posts: 409
Likes: 0
#5 and #6 plug wires cannot be anywhere near each other. Close proximity of these plug wires sets up what Ford calls induction crossfire. Because the later 302's used the 351 camshaft and firing order they even put a sticker under the hood on some of the early ones showing the correct wire routing and #5 and #6 should be crossed at 90 degrees to each other at the cap and be on the outside edges of plug wire separators.
Hotshot
Joined: Oct 2003
Posts: 17,799
Likes: 104
From: Ashland City, TN
Thanks fordtech1, i might be haveing that problem, i'll have to check it out for sure.
I'm haveing troubles with mine though, cause of TPS, and probably MAF sensor. So mine runs crappy at all levels. =)
I'm haveing troubles with mine though, cause of TPS, and probably MAF sensor. So mine runs crappy at all levels. =)
