Hey folks. I've been having an intermittent problem with my 99 1500 5.2 . Sometimes it won't idle or it bucks at speed. My question is if the fuel pump is going bad will it set a code or CeL? Thanks for the help

 

The fuel pump itself won't set a code, but, if you are not getting sufficient pressure/volume, the PCM will start whining about running lean.....

Sounds like what you are experiencing is misfires though. When's the last time the truck had a tuneup? Fixed the plenum yet?

 

Yeah I did the plenum about 2 years ago. I'll try the tune up next. Thanks again

 

Oh it is definitely not running lean. I pulled a few plugs and they seem to be kinda rich, sooty black. Plus I've already changed the Map sensor and IAC

 

Post a pic of your plugs?

If it really is running rich..... how old are your O2 sensors?

 

Its been a while since I changed the O2s, less than 100,000. Is the pre-cat O2 more important than the post-cat?

 

Pre-cat. NTK, or Denso sensors only please. Our trucks don't always like the Bosch sensors that much......