Hey guys, I recently redid my exhaust system on a 88GX (automatic). I replaced everything from the exhaust manafold to the mufflers. The 2 precats were removed and the main cat replaced with a highflow. The piping was also upped to 2.75 inch.

Before the new exhaust i could hit 200kms on the highway in drive no problem... Now around 120Kms in drive i'm at 5000rpm and the car fleels really lite... like its loosing power. The only way to go faster is to turn on the over drive or it will redline in drive.....i didnt even thing that was possible in an automatic....my question is did i open up the exhaust too much and loose backpressure? is my o2 sensor going and i'm gettin a bad fuel to air mix or am i hitting some sort of fuel cut?

i'm still running a stock air intake system...do i need to throw on a K&N??

I'm not a mechanic and dont pretend to be one all suggestions welcome...Thanks

Damien

 

Did you do anything about the split-air pipe (that pipe that ran to the cat?) If not, chances are your aux (5th & 6th air ports) aren't opening.

 

If you mean the air line that ran to the main cat, then yeah i ran it back to the new main cat.

 

Could be possible there's not enough air from backpressure to open your ports, in which case you'd have to rig it to your airpump. I'd just wire them open, drive it around and see if it's better (will probably suck down low because you'll lose your torque) Just search for wiring the aux ports, and if that fixes the problem, search again for airpump aux ports, should find something about how to fix it.