Dropping 1 cylinder part throttle.

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I have an interment miss fire on 1 cylinder between roughly 10 and 50 percent throttle. give it enough petal and it will clear out, no stumble at idle or at just cracked throttle.

The wide band goes full rich when the stumble appears probably indicating its a spark issue. the injectors are PTE 880's and are pretty new. The data logs indicate nothing unusual.

The dropped cylinder used to happen very rarely, it has been getting progressively more frequent.

 

[WORPeclipse]

Coil pack or wire cutting out on you? Causing it to drop spark.

 

[cwriley]

is it misfireing for sure or just dropping in rpm's? if throttle position sensor has a dead spot on the resistor the voltage will drop to 0 until its past the dead spot.

 

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Interesting comment on the TPS Ill check the logs for any evidence of this.

It truly Feels like I am dropping a cylinder, power drops, throttle becomes less effective, ya get that ugly Braaaaap sound that makes ya damn sure your not firing on all cylinders. and the wide band pegs rich.


On the coil pack. I believe dropping a coil or wire would result in loosing two cylinders on our setup. Is this assumption correct?

* other interesting symptoms: It does not happen untill well after the car is warmed up and the engine bay is good and hot. Idle and WOT are still normal, even on the wide band.

 

[cwriley]

u check tps with ohm meter just hook it up and turn the throttle and it should read between 0 and 5 volts if i remember correctly, if it drops to 0 u have a dead spot and needs to be replaced. and i do believe you would drop 2 cylinders if u had a bad coil, when was the last time you changed wires and plugs?

you can also test wires with ohm meter depending on what brand/type of wires each has a couple thousand resistance and u can measure them if one is less or more than spec then its a bad wire. (i believe each resistance will be differend depending on length so i would look up specs)