ENGINE IS RUNNING ROUGH

2003 Chevrolet Silverado

Tiny

bobwheelerjr

December, 24, 2012 AT 3:19 PM

Check engine light came on, scan said mass air flow sensor, replaced still ran real bad with misfire's. I changed plugs still runs bad. It will not idle and runs rough?

FOUND 4561 RELATED QUESTIONS

Running Rough

27 ANSWERS
34 IMAGES

Idles Rough/changed Ects

37 ANSWERS
3 IMAGES

28 Answers

Tiny

JDL

December, 24, 2012 AT 3:23 PM

Do you still have the maf sensor code? If so, unplug it, see if it runs any better.

Tiny

bobwheelerjr

December, 24, 2012 AT 3:26 PM

No the p102 code is gone but p300 now there because of multp- misfires

Tiny

bobwheelerjr

December, 24, 2012 AT 3:27 PM

I unpluged the old one before and still ran bad, that.S why I replaced it

Tiny

JDL

December, 24, 2012 AT 4:20 PM

I see, check for vacuum leaks around the throttle-body and intake manifold. What about your plug wires? Run the vehicle in the dark, raise the hood, do you see arch running anywhere? I'm not sure of engine litre size?

Tiny

JDL

December, 24, 2012 AT 4:23 PM

I've been having computer trouble. When you look at one of my posts, what do you see, to the left of, "answered by", I see a box with a red x and the word, "tiny". Thanks

Tiny

bobwheelerjr

December, 24, 2012 AT 4:44 PM

First off it's 5.3, When I was coming back from up north from hunting it ran fine over 250mi. No issue's. Then it started to run bad after stopping at stop light. You know what else I already did, the throttle body was replaced last year. So now i.M leaning towards a vacume leak or pcm? Thanks for your help on this issue. (:

Tiny

bobwheelerjr

December, 24, 2012 AT 7:26 PM

So here I am in cold garage, sprayed carb cleaner all around intake no change at all. Re-scan again get code for map sensor so replace it same thing! Po106, while it's sorta running pul coil connectors and #1-2-3-4-5 are dead no change in running so swap coil pack from a good hole and still dead! So are we looking at pcm or other area?

Tiny

JDL

December, 24, 2012 AT 9:37 PM

Did you check for primary voltage at the ignition coil? Pink wire goes hot with the key on.

http://postimage.org/image/522beg0q5/

Tiny

bobwheelerjr

December, 24, 2012 AT 10:29 PM

Checked the voltage on coils and there hot w/key on

Tiny

JDL

December, 24, 2012 AT 11:05 PM

Use an led testlite between voltage and control wire, crank engine, is there a pulse? Check the grounds, also.

Could be a computer issue,but, if a coil or something caused computer to go bad, you have to fix it before installing a new computer.
Click on the link for wiring info.

http://postimage.org/image/y568b7ne3/

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