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-   -   Random misfires after new plugs (

mrjoshyman 06-24-2016 12:38 PM

Random misfires after new plugs
Here are my engine mods:
- DP
- cat back
- turbo inlet

I recently got my plugs changed to the Denso ITV22 and had them gapped per Cobb's recommendations at .026” - .028” (0.66mm – 0.71mm). Since then the car has not been doing well under load. Most recently I've been misfiring and thus losing power while accelerating moderately hard -- not a good place to be when trying to merge in traffic or switch lanes. As a result I got the CEL P0300: random misfire detected.

Any idea why this would be happening with new plugs? Do you think the place I got it installed at may have improperly gapped the plugs? Would resetting the ECU by unplugging the battery help anything?

Any suggestions are much appreciated.

WetzMS3 06-24-2016 12:40 PM

Check the plug gap yourself and make sure coil packs are seated and tightened.

Djohns 06-24-2016 01:09 PM

Also a fuel pressure regulator would cause a random misfire.

sheston 06-24-2016 07:41 PM

I would pull the plugs and check the gaps. Also try the coil stretch mod or go for the solid copper wires.

I don't suppose you got gas somewhere different, meaning bad gas?

mrjoshyman 06-24-2016 07:56 PM

i brought it back to the shop where they installed the plugs turned out they gapped them way off. they're buying me new plugs and installing them which is good on them at least for admitting the mess up

WetzMS3 06-27-2016 07:42 AM

Gap and swap your own plugs, prevent this nonsense.

anavrinIV 06-27-2016 07:57 AM

Run stock heat range plugs, you don't need colder ones

g00s3y 06-27-2016 09:03 AM

Has mods, but no HPFP internals and doesn't know how to change/gap spark plugs. Then takes it to a place that can't even do said simple work correctly.

Should probably sell the car and get a Kia with a 10 year/100,000 mile warranty and no mods. Will have much less of a chance of blowing the engine.

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