I have a 2003 Chevy S10 with the 4.3L V6. I drove it in the morning fine but that afternoon I went to drive it and it would not idle. The engine will turnover and start but it will only idle so long as I keep my foot on the gas at 1500-2000 rpms and as soon as I let off the gas, it drops to 0 rpms and stalls. The check engine light and battery light are also on.

I pulled the battery and alternator off and took both to Advanced Auto Parts for testing. The battery was low, but after 24 hours of testing they said it was charged and good. The battery is from 11/18. The alternator tested fine but I didn’t believe them, so I took it to four additional stores and had it tested a total of 5 times, 3 pass and 2 fail with the last test passing at 14.1 volts on their machine.

I decided to put everything back together and when I did the truck started right up and ran fine for about 25 miles. Now it is back to not starting without my foot on the gas just as it was before I took everything apart.

So currently I have the battery light back on, a P0507 (Idle Control System RPM High), and a P0420 (Catalyst System Efficiency) which I believe in unrelated and not urgent. I have an alternator on the way and am going to charge my battery again. I am preparing to address the P0507 but am still concerned that if that is what is was causing the truck not to start, then the battery light would not be one. I think I am going to just change out the alternator and see if that fixes it, but I also don’t want to do that unnecessarily. I should also say I am not a mechanic, just trying to do what I can to avoid taking it to one. Does anyone have any suggestions or has anyone dealt with this before. Thanks in advance!

 

Did you look for any vacuum lines that may be cracked or loose?

The next thing might be the throttle position sensor.
I Hope you get it going again

-Rexx
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