My car has been running like shirt lately. It only happens at high speed mostly in fifth gear. At part throttle, rpm begins to rise and all of a sudden it jerks like the car was chained to a tree or something. What the hell is wrong with it? Any help would be appreciated.

 

I think a lot of peoples Evos do that. Mine did it in 4th and 5th so I had to turn the boost down. You are getting boost cut. It probably happens in the middle rpms right? I think it has something to do with aftermarket intake afftecting the maf and increased boost due to aftermarket exhaust and mbc. If you have a mbc, just turn it down a little. A flash should fix the problem. Al at Dynoflash can get rid of the boost and fuel cut with his flash.

 

what mods do you have?

if you have basic bolt ons then you are probably hitting boost cut

get a flash or bigger injectors

 

do you have a SES light? If so that sounds like the P0300 code.

 

My mods are manual mbc, downpipe, and catback. Yes I did get a SES once when it happened.

 

if the SES light is on does it effect how the car runs?

mine is on because I removed the cat... but I plan to get the kit thing that will hookup to the ecu so the SES light isnt on

 

EvoVIII: Yes the car is effected if the SES is on. Usually performance is degraded but in the case with the cat removed or HFC installed, I have found my car to run richer and stronger when the SES came on. Not sure that is the norm.

showoff: The orginal issue (car running bad) probably because of crappy gas. High boost conditions and bad gas in the tank will either get you boost cut, fuel cut or timing pulled; all expose them self similar to the way you describe.