Car Sputtering?

[BOOSTJUNKIEGSX]

>>FP 16g, 550`s, 255, FMIC, ported manifold/o2, Apexi gt spec DP/exhaust, 20psi<<

Sputtering Symptoms -
1-When the car is being driven on the highway and am in 4th gear around 3000 rpms, if i ride the gear out throught the rpm band not flooring it in the upper rpms and holding it , the car will go into a mode where i could give 100% throttle and the car will not go. Feels like it is running on 2 cylinders. ( like a stuttering when throttled)
2-When the car is boosted through 2nd n 3rd gear to 7000 rpms the car will also sometimes ( not always ) go into RETARD mode in 5th gear.
3-If im driving on the highway and am in 5th gear and do over 100+ mph and then back off the throttle 100% - the car will sputter when the throttle is floored again making it seem like its running on 1 cylinder **when throttle floored it kinda makes it sound like a wrx`s exhaust**

***The only way to get the car back to normal throttle and running normal is to either put the car into Neutral while driving waiting for the rpms to go down, or by pulling over , sometimes having to shut the car off, and then back on??***

 

[Scott_S]

I had that problem, I changed the 02 sensor and did a boost leak test and found some big ones. I'm not sure which one helped the most but do a boost leak test and I bet you find at least one.

 

[BOOSTJUNKIEGSX]

Today i spent tons of time focusing on boost leaks and i found a few. Having fixed them the car still did the same thing. Using SEAFOAM I found that i have a huge exhaust leak from the manifold to turbo. Could this be the problem?

 

[Scott_S]

Its possible. I've heard of exhaust leaks causing misfires and if any fresh air is getting in it would tell the O2 sensor that your motor is leaning out and add more fuel causing it to studder like your saying

 

[femmeDSM]

I found that i have a huge exhaust leak from the manifold to turbo. Could this be the problem?

Absolutely.
Car will run like crap-ola until you fix that.

 

[BOOSTJUNKIEGSX]

Thanks guy`s! I do have a question about a manifold to turbo gasket. i have an upgraded gasket which is a metal gasket. I cannot get it to seal! I took the manifold off numerous times and sanded the surfaces to make sure they are smooth, level and nothing interfereing but it always leaks. I also torqued the bolts to make the seal tight but no luck.. I cant win..Im thinking about getting a stock gasket from mitsubishi! Could i use the atv sealant?....options

 

[Scott_S]

I had one of those metal ones to and it leaked really bad. I had my manifold machined flat and got a felpro gasket and that seemed to work pretty good. When I took it off again it had a little leak but other than that it was fine.