1994 Trans Sport 3.8 missfiring

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tp - 06 Jul 2006 01:22 GMT

O.K. I have new info on my problem. I decided to power brake it when
i got home tonight. I just slowly increased the R.P.M.s Sure enough
right at 1600 it started to miss, then went away at 1800. No miss above
or below that range. It sounds like it is just one cylinder, not
multipull misses. Whats up with that? A missfire in a mid R.P.M. ??
Maby at that voltage range one injector is weak. Any more thoughts
would be helpfull. Thanks, TP

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Kevin - 06 Jul 2006 03:36 GMT

> O.K. I have new info on my problem. I decided to power brake it when
> i got home tonight. I just slowly increased the R.P.M.s Sure enough
[quoted text clipped - 3 lines]
> Maby at that voltage range one injector is weak. Any more thoughts
> would be helpfull. Thanks, TP

Secondary voltage demand goes up as you put a load on the engine. If there
is any weakness in the secondary insulation (plug wires, coil molding, spark
plug insulator etc) then it may only arc when the voltage reaches a high
level. Secondary voltage will drop off near wide open throttle and arcing
may discontinue. This is just one possibility. TPS is a good guess also. The
TPS is easy to check with a volt meter, but the secondary KV requires a bit
more sophisticated equipment to monitor. If you are going to change parts on
a guess, I would try a set of wires before a TPS.

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Kevin Mouton
Automotive Technology Instructor
"If women don't find you handsome, they should at least find you handy"
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