So I have a 2005 gsr and has hks 272, cams ported fp green, injen ic piping, godspeed intercooler and a few other mods. The car has ran great for me till I just recently changed the exhaust manifold to a megan header and the car ran good for a couple weeks and then all of the sudden I started getting horrible fuel mileage and drivability became horrible, my afr started going rich (11) while just normal driving and as soon as u go wot it would start cutting out and bucking and wouldnt accelerate at all but if u let out and hit wot again it would usually take off. So I started looking around and found the megan header was cracked so I put my factory ported manifold back on thinking that was my problem, but my problem was still there so I pulled sparkplugs and they were whitish but the ceramic insulater was a redish color and the part that the electrode arcs off of way a yellow color,so I put an old set of plugs in that I had laying in the garage, still same problem so next I went and ourchased a new front o2 sensor but the car still cuts out and bucks but now my spark plugs are black. Im am starting to get pretty frusterated with this car and any help would greatly be appriciated cause im lost. Lol

 

Bump

 

Throw in a set of new spark plugs to see how it runs with the stock exhaust manifold. I'm sure that cracked megen manifold wasn't helping the situation and also when installing a different exhaust manifold I would advise a re-tune to have the car run properly.

 

That was the plan but I never made it to the shop before it cracked ordered the soark plugs hopefully will be here tomorrow

 

How many miles did you get out of the megan header before it cracked?

 

Im not sure it was cracked when I got it and I tig welded it and it jus cracked in other places after that

 

Well I cleaned the maf and put new bpr8eix plugs in gapped at.026 and car ran great all day and I start it uo today anf its back to the same thing

 

Have you done a boost leak test?

Like, a real one. With soapy water and spray bottle?

 

Not yet that was the plan yesterday until I drove it and it felt way better until today. But yesterday I had a vac line pop off and it wouldnt build more than 8psi but after.I fixed that it is now back to 28psi

 

Do a boost leak test with soapy water still. Boost leaks should be checked at every oil change or AT LEAST every other oil change depending on how much psi you're pushing.

 

Ok ill try thay thanks

 

Try another set of Coils and Wires, the plugs are black from not burning fuel and why our running so rich.

 

gap your plugs at .020, I would bet you are getting spark blow out. i had that issue after i installed the fp black. i run .020 and it runs great.

 

Now the plugs are mainly black now but the metal piece on the end is grayish white

 

so you gapped them at .020 and still have the problem?