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Please Help... P0300 Code After Plug And Wire Change.

willprit

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willprit Enthusiast

willprit

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I just installed new NGK TR55IX plugs and OE plug wires on my 2001 5.3 Silverado with 65,000 miles. I did this as an exercise in preventative maintenance, but now the engine idles roughly, sputters on the road and is sending me a P0300 code (misfire)... I rechecked my work and even purchased a new plug wire set, thinking I might have a bad wire.

 

It's still running roughly after rechecking all the wiring once again... now I'm wondering if I might have bumped something and should look somewhere else for the problem. Has anyone had this happen or got any ideas?

willprit Enthusiast

willprit

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oh man, there are alot of TSBs for that PO code......

 

Do you mean this happens enough that there are TSB's about it?

willprit Enthusiast

willprit

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did you mean to post something cause it came up empty

 

Sorry about the lack of posting skill... I'm a newbie and am trying to get this misfiring problem fixed. Thanks for checking.

jrrod2004 Senior Enthusiast

jrrod2004

Posted
Posted
oh man, there are alot of TSBs for that PO code......

 

Do you mean this happens enough that there are TSB's about it?

 

 

 

yeah like 11 or so.......all related.........

minibike132 Senior Enthusiast

minibike132

Posted
Posted
oh man, there are alot of TSBs for that PO code......

 

Do you mean this happens enough that there are TSB's about it?

 

 

 

yeah like 11 or so.......all related.........

 

 

 

There isn't a tsb(that I know of) that says I just replaced OE with not OE and a p0300 came up.

jrrod2004 Senior Enthusiast

jrrod2004

Posted
Posted

well here is the list:

 

 

#03-06-04-030F Various Driveability Symptoms Due to Clogged Fuel Injectors, MIL/SES DTCs P0171, P0172, P0174, P0300, P1174, P1175 (Clean Fuel Injectors and/or Perform Injector Test With AFIT - CH-47976) - (Dec 10, 2007)

#PIP4138B GEN III Or GEN IV V-8 Engine Misfire - keywords P0300 arm cam camshaft lifter wear worn engine L33 L59 L76 LC9 LH6 LM7 LMG LR4 LS2 LQ4 LQ9 LY5 LY6 misfire miss rocker roller rough valve - (Oct 8, 2007)

#PIP3232B Cold Engine Idle Misfire Or DTCs P0171 P0174 - keywords 4.8 5.3 6.0 air cold crack hesitate idle intermittent internal intake leak lean misfire miss P0171 P0174 P0300 power rough surge vacuum - (Feb 7, 2007)

#PIP3055A P0300 Cylinder 7 Misfire Due To Fuel System Contamination - keywords CEL contaminated DTC engine gas L59 L76 L92 LC9 LMG LR4 LM7 LY2 LY5 LY6 LQ4 LQ9 miss P0302 P0307 P0308 SES tank water - (Sep 26, 2006)

#06-06-04-046 Information on Engine Misfire MIL/SES Light Illuminated or Flashing DTC P0300, P0301, P0302, P0303, P0304, P0305, P0306, P0307, P0308, P0420 or P0430 - (Sep 12, 2006)

#02-06-05-004b Info - Misfire DTCs P0300, P1380, P1381 and Catalytic Converter Damage Due to Installation of Alarm Systems - (Feb 14, 2006)

#PIP3375A No Start, Rough Idle or Erratic Injector Balance Rates - keywords 6.6 crank cut DTC fuel hesitate high LB7 LLY P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 P0335 P0336 sensor SES shift - (Aug 19, 2005)

#05-06-04-007 Poor Engine Performance-Misfire, Rough Idle, Stalls, Engine Cranks but Does Not Run, SES/Check Engine Light On, DTC P0300 Set (Inspect Distributor Ignition(DI) System Components, Replace as Necessary) - (Jan 28, 2005)

#PIP3292 Diesel Engine Injector Balance Rates All Showing Zero - kw 6.6 LB7 LLY rough idle miss misfire driveability inoperative P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 - (Jan 17, 2005)

#PIP3081 SES Light and P0300 When Towing , Cruising Uphill or on Hard Acceleration - kw 4.3 5.0 5.7 accelerate cruise cylinderhead DTC L30 L31 L35 LF6 LU3 P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 - (Jul 23, 2004)

#PIP3056 97-05 Vehicles with 4.8 5.3 5.7 and 6.0 Gen III V8 Engines and Misfires on One Bank - kw CEL diagnostics driveability DTC P0171 P0172 P0174 P0175 P0300 P0301 P0302 P0303 P0304 P0305 P0306 P0307 P0308 - (Jul 12, 2004)

 

 

Not sure if you have seen these or not mike - or maybe I am wrong?

svensk Senior Enthusiast

svensk

Posted
Posted

I see you went with the iridium plugs. Check your gap and make sure they're the new GM recommended .040 instead of .060.

willprit Enthusiast

willprit

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Thanks for the suggestions everyone... I plan to start with the plugs in the morning and check for cracked insulators and proper plug gaps. I did check the gap before installing and found that they were set at .060 in. from the factory... will try regapping at .040 in. I feel better now that I've read your responses because there may actually be a reason why my truck is misbehaving. It's tough when you do something that's supposed to make it better and then things just get worse... definitely getting smarter though!

Draenor Senior Enthusiast

Draenor

Posted
Posted
Thanks for the suggestions everyone... I plan to start with the plugs in the morning and check for cracked insulators and proper plug gaps. I did check the gap before installing and found that they were set at .060 in. from the factory... will try regapping at .040 in. I feel better now that I've read your responses because there may actually be a reason why my truck is misbehaving. It's tough when you do something that's supposed to make it better and then things just get worse... definitely getting smarter though!

I wouldnt try re-gapping the plugs. You will damage them. It its not visible, the tip could break off in the engine while it is running. Just go buy the correct ones.

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