Rough idle problem 2000 silverado

[Laydout98]

I have a 2000 chevy silverado 5.3 with 230k miles. When its in park it idles fine but when in gear like your about to take off or at a red light it idles real rough sounds like its about to die. It doesn't do it all the time but most of the time it does and when your driving down the road it runs perfect. I have replaced the fuel filter,air filter also changed the spark plugs, wires and have cleaned the throttle body. Has anyone had this problem or know what the problem could be? Any help would be appreciated thanks.

 

[SAATR]

Clean the idle air control motor pintle valve and air passage and see if it improves. If you can get a scanner that reads live data, watch the IAC motor's position and the desired idle and see if it is moving to compensate. If not, or if it's ineffective, it may need to be replaced.

 

[Laydout98]

I had it scanned it threw alot of codes I guess you would expect that with 230k miles lol.

here they are
P0171- System too lean

P0174-System too lean

P0300 Random/Multiple cylinder misfire

P0332- Knock sensor 2

P0420-Catalyst Efficiency Below threshold

 

[CodyB]

Check your wiring harness going to the O2 sensors, it sounds like a stick or something could have caught and damaged it from all the codes but the misfire and knock sensor codes. How long ago did you replace the fuel filter, I would imagine that could cause most of those codes, and when its under power the filter is flowing enough, but when idling the flow could be restricted?

 

[Mike]

LSX will not run correctly with those codes. If you can't diagnose your problem then take it to someone who can. And stop driving it around until it is fixed.

 

[joshjuniorr]

LSX will not run correctly with those codes. If you can't diagnose your problem then take it to someone who can. And stop driving it around until it is fixed.

hate to jump on a "wagon" but hes right bro. If you keep driving it its only gonna cause more problems and make the actual root of it all harder to find. as said above check the o2's if they're unplugged or the wires are broken itll make the motor run lean and cause multiple misfires as well as that cat code.