OK I have been having this problem since I bought my turbo my turbo is a TDO6 20G I have invidia O2 outlet 3 inch downpipe and I have the HKS exhaust system as well 3" catalityc converter, Ok I post another thread before asking what could I do with my turbo I have changed the lower intercooler pipe,upper intercooler pipe,tried many blow off valves, did a boost leak well have done so many things and still not working, this is what the turbo does wen on WOT before hiting more then 16 PSI it holds it great but as soon as I want more boost like close to 20 or more I get the car to start like a missfire but hasn't have any missfire or anything it sounds like the air coming out gets stucked or something but whell I have changed the boost controller to a manual???

 

Is your car tuned for the mods?

 

yeha the car has been tuned I have HKS 272/272, FIC 680 fuel injectors, 255 LPH fuel pump,spearco front mount intercooler,HKS DLI ignition, and a lot more stuff it was fine before with the TDO5 16G was boosting 21 PSI and holding it fine I just wanted to have more boost so I got this TDO6 20G and a reflash since then it stopped working!

 

Try running one step colder spark plugs.

 

Punctuation first. Boost leak test second.

 

Thirs, check your plugs...did you? Sounds like you should definitely be running one step colder. With my mods I couldn't get 7ES's to work at any gap so I went to 8ES's and it's perfect.

 

Make sure the vacuum lines are hooked up correctly from the turbo/wastegate to the boost controller. If not u will only ba able to boost a certain amount and ur car will act funny under WOT. Also well you said you did a boost leak test, check to make sure ur vacuum line to ur fuel pressure regulator is connected too.

 

all connections are tight nothing has any un wanted air flowing in to it.

 

well I do have the one step colder I have the 8es I also disconnet my boost controller and hooked the stock ones back on and it was doing even worse so I reconnect them just as the manual on the greddy boost controller says and still it runs strong and good as long as I run less then 17 PSI let me know what else do I have to check so I can run higher boost with out doing the funny stuff it does on higher PSI?

 

many thigns can cause misfire. leakage, wrong sparkplug gap, running too rich, etc..

 

what's the gap that I should be running with this plugs? and no I'm not having any misfire

 

If it was based on the ignition system (plugs, gaps, etc.), wouldn't it throw a P0300?

 

I do have the 8ES and I just went out and gapped at .024 but never had any PO300 CODE or anything like that before, I will be changing the plug wires tomorrow

 

try gapping a little smaller. maybe like a .020

 

What are you using to tune your car? vboy425 was right about if ur car running to rich it will cause problems like your seeing. If ur using a any kind of piggy back i would check the setting for the MAF sensor and basically just go through it all make sure its all set right..