Hi guys, I just boughta an 02 WRX wagon with 143000 miles, car is in very nice shape.

The problem is that the engine sputters at approx 3000-4000 rpm, while there is't much power. But if you cntinue to 6000 rpm, it has decent pull, what could it be? Any ideas?
Thanks in advance

 

OK guys, I had Autozone scan the codes. It came up as pre cat O2 sensor in cylinder bank 1. Anyone out there have any experience diagnosing, or replacing this sensor. Which side is cylinder bank 1?

Does anyone have any suggestions before I go out and buy a sensor, which I am afraid may not be the problem.

I saw Bosch sensors online for about $75.00 vs $150.00 at Subie dealer. Anyone try the bosch?

 

Anyone?

 

im pretty sure theres an o2 sensor in the up pipe, and one after the third cat. subaru parts are always expensive, but 99% of the time youre getting the best parts money can buy.

 

I can't see the O2 sensor, any photo illustrations?

 

hello, i too own a WRX wagon. what if any mods are on the wagon? with that many miles it could be a bunch of things spark plugs, fuel filter, air filter, bad gas ect: let me know. lol

 

It has a Cobb tuning catback, 143k miles. I already ran a bottle of Techron with a fresh tank of gas. I do have a K&N airbox replacement air filter I changed the fuel filter yesterday, I will be installing a new O2 sensor, and NGK iridium plugs in the next two days.

 

hello, i just read something on another forum about the intercooler hose. check if there on tight, no leaks. try using soapy water on them and look for bubbles. lol

 

the o2 sensor is accessable through the pass. wheel well, it's on that side of the exhaust manifold. Not hard to do, just sure you get an 02 sensor wrench. The sensor in the uppipe is an egt sensor. What was the actual code?

 

I finally replaced the O2 sensor with an OEM one, installed NGK iridium plugs, and a fuel filter. The car still sputters. What to do now? Any experts in NJ, Bergen County?

 

Does it sound like a cat problem? When you are awaiting boost and su surge forward, you instead go slower. Part throttle is not as bad, anything more than part throttle in the 3000 rpm -5000 rpm its going to stumle and go slower.

 

Doesn't sound like a cat problem. Maybe an iac problem though.

 

What is a iac?

 

hello, yeah what's an iac problem? a friend who i replaced the fuel filter and spark plugs had a similar problem. the car would buck and surge above 6000rpm, you really could tell in first gear. he then took it to the dealer and they told him it was some type of throtlle postioning senor,(TPS). they replaced it and the car ran fine. now it looks like you have to go to the dealer. i do my best to avoid the dealer. you might just call and ask to talk to the dealerships subie guru. maybe he/she can put you in the right direction. lol

 

The check engine light came on again, ran the code, cam up as bank 1 lean, again. What now guys?