[CarterContos]

2014 VT 40k miles. When hitting boost car would slow tremendously and backfire like crazy. I was 40 mins away from my house when this started and I drove back. As long as I keep my rpm’s below +/-3k I was driving smooth as regular. When ur first started happening, I pulled over in the parking lot and we had an inactive code for a misfire. All spark plugs seemed fine but that was about as much as I was willing to do in a food lion parking lot at 1am. After clearing the code, I repeated the backfire, this time no code was set. Any ideas as to what it could be. Thank you. I can answer any questions that could help diagnose

 

[CarterContos]

start with checking the plugs.

I did, nothing seemingly wrong there, all gaps correct, no broken or carbon covered tabs. Not possible it’s a timing issue is it? Chain didn’t skip a tooth or something. It’s really odd bc I can idle and drive just fine, but everytime I get it about 3-4K rpm it slows the car (almost like an engine brake/retardant) and it backfires

 

[CarterContos]

You need proper plugs from a 16+ VT with .028" gaps, oem coils, and run 91+ octane fuel. If this does not fix it then you likely need aftermarket low pressure fuel line.

I’m buying new plugs on Amazon now. Don’t believe there’s anything wrong, me and my friend I was with are both diesel mechanics and they looked good to us. Been running 89 octane but will be switching to 91 next fill up. I installed a modified axle back exhaust on it a couple weeks ago. Straight pipe thru the muffler. Even tho there was no sensors or anything, would the little loss of back pressure affect anything? I wouldn’t think so, but it was the only resent change to the car within 5k miles