2003 Silverado runs terrible

Asked by Will Jun 21, 2016 at 02:31 PM about the 2003 Chevrolet Silverado 1500 LS Extended Cab 4WD

Question type: Maintenance & Repair

Bought a Silverado 5.3 vortec and it runs rich, I can tell by
the smell and that it dumps black smoke out of the
exaust. Sometimes if I don't give it enough gas when
initially accelerating it'll feel as if it has no power(at this
piont the check engine light starts blinking) , won't
respond until you floor it(black smoke).  When I bought it
the guy claimed to have put a "tuner" in it? But he said it
was just a code that like unlocks the computer so he
could mess with the settings.  He has the tuner on there in
order to help turn the 35s.

5 Answers

159,315

Have the truck scanned for trouble codes and either post them here or do some "googling" on the codes. Could be an O2 sensor or something else. Hopefully the previous owner did not mess around with the fuel settings.

I ran it through the code checker and it foxes say 02 sensor. They guy for some reason said he had them disabled as they were interfering with the "tuner". Why can't people just keep shit stock... And also the truck idles real poor. No powersteering if you don't give it any gas, idled at about 500-600 rmp

159,315

I would get the tune out of it and put it back to stock to see how it runs. You can always use the tuner to correct the speedo for the oversized tires only. Best of luck with it.

Thursday I go to the shop to get it out. 45 min away shop is gonna be along drive with an exhaust manifold leak and a pretty awful running truck lol. Thanks for all your help!

159,315

The exhaust manifold leak could be the cause of it running rich. Sometimes exhaust leaks mess with the O2 sensors causing an over rich mixture.

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