2.9 missing on two, maybe three cyls.
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Senior User
Joined: Nov 2001
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From: beverly, Ohio
2.9 missing on two, maybe three cyls.
I just bought a 90 BII 2.9 auto and it's got a little problem. When you first start it and drive off all cyls. fire and it runs great. After about three mins. of driving if you press the accelerator more than half way it starts to miss. I pulled the codes and got a 41 this afternoon. I know this is o2 sensor code, but would the o2 sensor cause this problem? It's almost like it looses fuel pressure on two cyls. While you drive it, if you do,nt give it more than half throttle it runs smooth with no misses. Almost like it only happens when the engine is under a load.
thanks,
thanks,
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Joined: Sep 2004
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The way you describe your problem sounds to me as if either (1) one or two of the spark plug wires are breaking down under load when the cylinder pressure increases, (2) the coil is breaking down as it heats up, (3) you have a carbon track at two adjacent towers on the distributor cap, or (4) your truck has the UIM-style module which, of course, can actually create a misfire if the sensor(s) pick up a bad reading or malfunction. Of course, I do not know if your truck has the UIM-style module instead of the TFI module that almost all of them used. I have only seen two of them, as a matter of fact. Also, just to play it safe, check and make sure that BOTH screws holding the distributor cap to the distributor body are fully tightened.
I do hope this is of some benefit to you!
I do hope this is of some benefit to you!
Postmaster
Joined: Dec 2001
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From: UT
I pulled the codes and got a 41 this afternoon. I know this is o2 sensor code, but would the o2 sensor cause this problem? It's almost like it looses fuel pressure on two cyls.
Thread Starter
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Senior User
Joined: Nov 2001
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From: beverly, Ohio
mrshorty, you did bring it to my attention that I did do the KOER test and got the 41 code but I read the code wrong in my manual. leaning toward a fuel problem, have to check pressure this evening.
thanks for all suggestions
thanks for all suggestions
Thread Starter
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Senior User
Joined: Nov 2001
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From: beverly, Ohio
this evening I pulled the bronco in the garage and opned the hood and it was like a christmas under there with all the sparks jumpin around. Gave it a tune up (plugs, wires, caps, rotor button) and the miss is gone. gonna pull the codes tomorrow and see if any are in it now. thanks for all the help guys
