Engine stumbles at 45mph

[Xscorex]

I fixed my p00178 problem but now Im having more trouble. at idle, I will occasionally get a misfire or rough stumble in the engine. It will purr fine and then Ill get one hiccup. This also happens at a very specific rpm and speed. It only happens at 1500 rpm when Im going between 40 and 45. The engine will stumble and jerk like it is misfiring. No check engine light. I haven't pulled the plugs yet.

 

[digglesworth]

Have you put a code reader on it? Sometimes you can have stored codes without a CEL. Happened to me with a bad coil pack. That does sound like an odd scenario. Sorry I can't be of more help.

 

[Xscorex]

For a minute I thought it might be tranny slipping but i dont think it is. Going down a hill at 45 at 1500 rpm it wouldnt jerk but once I tapped the gas It would get the jerking stumble in the engine. Another weird thing is it wont misfire if i put it in nuetral and give it gas. Just at idle in gear at a redlight. I saw simething about doing a camshaft "relearn" on the colorado boards but dont know if it applies to the h3

 

[SlikRick]

Mine turned out to be a broken wire, 300 dollars in trouble shooting time to find it.

 

[HummerRoller]

Mine was a terribly long wait for the cel to come on... misfire on a coil

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[deserth3]

Throttle body position sensor or throttle position sensor,

 

[CaseyS]

The torque converter locks between 40 and 45. Could be transmission related.

 

[Xscorex]

Its the transmission.

Looking at my engine I noticed a broken bracket on my engine. The transmission filler tube bracket had broken and was flopping around I think Im losing transmission fluid. The rough idle must have broke it. about to check the level an see if it is low

 

[HummerRoller]

I doubt you are.. if you did, not even a quarter of a quart.... check plugs and coils.

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