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2003 s-10 Code P0303

2003 s-10 v6 4.3, Code P0303 Cyl 3 Misfire.

Pulling hard up hill , get flashing Check engine light ,Type 2 (Hard on the CAT)

Light clears, but code still there. Noticed for the last week, I get hard restarts, after about 20 minutes, of stopping. ( Cranks longer to start), as compare to 1/2 second after 1 minute. If i turn the ignition key to " On" for a second, then off, then crank,,the engine fires immediately,(as if I'm priming the fuel system).

I think I might have a leaking injector, or bad check valve in the fuel pump, or maybe a bad fuel filter. I am trying injector cleaner first. I also remember Chevy having trouble ,with sticky injectors a few years back...also I don't feel any drop in performance while this is going on.

I have 83,000 miles, on the truck, and I replaced the plugs, AC Delco Plats,at 41,000, the truck is still like new. Filter at 31,000. Thank you for reading this!

Reply to
Bumpy
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well, your plugs and filter are due......

Reply to
ScottM

Is there any arcing when looking at the engine bay in darkness (engine running obviously). It could be as simple as a bad coil or wire shorting to the block, etc. You may want to try swapping two wires to see if the problem moves to another cylinder. How does the fuel pressure test at the rail??

Thanks, Andrew.

Reply to
AWN

Sounds like you have a sticky poppet valve on #3. Try running a can of SeaFoam cleaner through it. You might also want to run a pressure test on the fuel system. You will see the pressure drop fast with the key off if the injector is leaking down.

Reply to
Steve W.

Steve,

Did GM still use that poppet design in 2003? I don't feel so bad for my 95 now if that's the case. It seems like the design needlessly overpressurized the fuel system to open to the poppet style injector. I thought they moved away to actual injectors but I've learned that you certainly know your stuff when it comes to these motors.

Thanks, Andrew.

Reply to
AWN

They used a remote injector with a poppet valve on the intake end. Not the spider style CPI like the earlier engines. Basically you have 4 versions of 4.3 in use. First they were carbed, next came the TBI, then the early style CPI, then the later style SCPI. The last version used an independent firing injector (basically an electronic version of a poppet valve) but was still fed from a central regulator block. There are kits that allow you to convert the earlier units to the latest design.

Reply to
Steve W.

Thanks Steve, The weather has been bad here, and I have not been able to get out and work on it. I put some Chervon Techron or whatever they call it. but it does not help..Ill try the seafoam. It just seems as though its an injector.

Is the pressure tap the same size as a tire valve? I had a 93 blazer, but I don't remember the size, at the time. Thanks again, Steve

Reply to
Bumpy

Not the same size valve. You can probably borrow the proper gauge from auto zone or advance.

Reply to
Steve W.

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