94 Ponitac SSEi Miss on #5 Cylinder. Help.

The car is showing a miss on the #5 cylinder, occurs only when engine is under boost from the supercharger. Occasionally also shows miss on #4 and less frequently on #6. This was found by using a scan tool.

Have swapped plugs, wires, injectors, injector wires, and coils with those from either #3 or #1 cylinder, but problem stays on #5. Also tried a new ignition control module. Engine runs smooth in the driveway at all rpms. Only misses under load and only under boost conditions.

I'm thinking fuel pressure regulator?? fuel pump??

The fuel filter was recently replaced. I run 92/93 octane.

Problem occured after car was parked for several months with only being started every couple of weeks and idling to operating temp. The car has

177,000 miles. Ran great before parking it.

Any help would be greatly appreciated.

Thanks, Jeff

Reply to
Jeff & Carol
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Could be the injector is sticking, gummed up, or failing. Either borrow or buy a Noid Light Set.

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Load orboost conditions would require more fuel than idle causing a poorlyperforming injector to only cause a problem then. Buy some test equipment.In the long run it's cheaper than just throwing new parts at it and hopingto fix it.

Reply to
FBR

Thanks for your response FBR.

Am I mistaken to think swapping the injector with one from a cylinder that is performing well is good enough to prove it is not an injector problem?

Reply to
Jeff & Carol

Look and see if that cylinder is the last one on the fuel rail. If it is, it may be the one that is becoming starved for fuel.

Reply to
Taz

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