I'm having an issue with my 2008 GSR and figured I would get some opinions before I start tearing into it. There are 36k miles on the car and it has a Blouch Dominator 2.0 turbo, custom 3" turboback exhaust, aluminum IC pipes, injectors (800 something I believe), and a 25psi pump gas tune by Slowmotion. I purchased the car two years ago for use as a DD with the mods already done.

I'm getting a misfire from 2500-3000 RPM in all gears when at 25%+ throttle. It will usually cruise fine at those RPMs, but misfires worse with more throttle. It is more pronounced when the car is below operating temp and when the outside temps are a cooler. The hesitation will range from a light stumble to completely falling on its face for a split second and usually accompanied with a backfire.

I checked the plugs (NGK iridiums) and they appear to be fine and the gaps are correct. I think I first noticed the issue about a year ago and it seems to be steadily getting worse. I searched the forum and found someone with a similar problem who had a bad coil. I'm thinking about ordering one and swapping it around to each cylinder.

Any ideas?

 

FPR hose? Just throwing it out there.

Good luck with it.

 

I used to get these on a Saab with a bad TB pos sensor. Bad coil might do it.

 

I am having this same exact problem. Did you find a solution?

 

when the car is not at operating temps, it uses many different values, such as mivec intake and exhaust and it will even use LTFT mid instead of low.

if the issues do not occur when car has proper temp, i wouldnt worry about it. either that or dont go >25% throttle on a cold engine.

 

Wouldnt a misfire from a bad coil throw a code? either way its worth a shot to get one and swap it around.

 

a misfire caused can throw p0300 for mutliple misfire and p0301-0304 for corresponding cylinder misfires.

 

Any ideas. I'm having this exact problem. Even when the car is warm I get bad break up and back fire when part throttle. I changed the plugs and it went away for about 2 weeks. Makes me wanna get rid of the car

 

Maybe you need to regap your plugs?