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Cylinder 5 misfire

I have a misfiring #5 cylinder on my 2001 Chevy S10 6cyl. Fuel pressure, plug and wire are ok. The scanner reads -61.7 and

-73.4 LTFT’s on Banks 3 and 4. Banks 1 and 2 read 20.3 and -3.1. I’m thinking I might have a bad fuel injector but I would like to be sure before I start ripping things apart. Any opinions would be appreciated.



That sounds like the next logical thing to me. How many miles on the truck? Have the injectors ever been cleaned (and I don’t mean a bottle of injector cleaner)?

You can check for proper function of the injector by using a mechanic’s stethoscope, or the poor man’s alternative, a long screwdriver cupped to the ear. Listen to all the injectors, and you should be able to hear a distinct clicking as the engine is running. A muted click or no click means problems. Before condemning the injector, always check the connector to it. If the clicking is muted, a thorough cleaning may fix it.

Thanks for the reply,
The truck has 93,000 miles on it and the injectors have never been cleaned. This vehicle requires removal of the throttle body and upper manifold to gain access to the injectors so the stethoscope test is not feasible. Does anyone have any idea of about how much the shop will charge me for cleaning the injectors?

Here’s one offer: As in the usual disclaimers, this does not constitute an endorsement of this service provider.

Here’s what is done, how, and why in a “fuel system cleaning”: