Alright, I've been dealing with this problem for a while and have finally decided to ask for help. My car seems to sometimes hesitate upon hard acceleration. The car will lurch foward and completely loose power, almost like there's no gas. RPM's stay steady, oil pressure is steady, boost looks normal, engine and exhaust temps are normal. Here's what I've noticed: 1.) Always when the car is warm (i.e. most of the time after I've been driving for 30 minutes on my way to work). This may be because I'm not driving hard when it's cold. 2.) Always in second gear immediately after a hard right hand turn. Weird, I know. 3.) Always hard acceleration 4.) Always around 3500 RPM's I bought this car a year ago and I've done the following: 1.) new clutch, pressure plate, and flywheel 2.) recent tune up with 1 step colder plugs 3.) reconstructed the stock airbox (it was missing the snorkus and front airduct) and added K&N filter I've checked for codes using my V1 Accessport. But this would only show CEL codes, right? I plan on doing the timing belt and fuel filter. I'm pretty close to going to see King but wanted to float this out there first looking for a cheap fix.
If you had to reconstruct the air box this leads me to believe the common problems of EFI have reared it's ugly head. Clean the throttle body, MAF and double check vac lines. That should take care of any problems
I thought about that. I assume it had a CAI at some point. The snorkus was gone and there was the snorkus delete/hole cover installed. The airbox was there with a paper filter sucking air from the fender well. Oh yeah, and the fender liner had been cut beyond recognition so there is no tell what made it into the airbox. I'll do that today. Do you guys normally use Subaru fuel filters? Or are the aftermarket ones just as good?
This is old but thought it might help someone if I updated it... The hesitation problem only occurred periodically, mostly in second gear. I recently did my timing belt and it started happening in every gear at WOT. Did some research and... Determined it was spark blow out. I checked the gap on my spark plugs it was at .030. Re-gapped them to .025 (thank you WJM, saw one of your previous posts) and problem's solved.