Trying to figure this out. I have an 01' Camaro Z28. When I left the military, I had my car shipped to the states. I already had tranny problems but didn't want an Italian mechanic touching her. I took it to a transmission shop and had the damn thing rebuilt. I chose the high-performance package (I have an A4). Don't know much about transmissions, just know the car works now. Anyway, I drove the car up here to Minnesota in January. The weather was cold. My car then preceded to start leaking oil. I replaced the PCV valve and oil pressure sensor. Problem solved. However, I'm posting this because my gas mileage has been cut in half, the car idles very roughly and there is a tremendous loss in power. I'm going to take these steps first.

1). Replace spark plugs and wires
2). Clean MAF, IAC and TB thoroughly
3). Replace o2 sensors

Ran some SEAFOAM through the gas tank the other day and ran at WOT which seemed to help. What I ultimately want to know is, does my car need a tune. It's been running sluggish ever since the new transmission was introduced. Any help would be greatly appreciated.

 

Maybe a tune issue but I would also get a new fuel filter just to be on safe side.

 

Forgot to mention I picked up a random misfire code the other day.

 

Vac leak or issue with a plug or wire. Buy carb cleaner and spray aroun the engine bay and listen for an increase in idle. Change your plugs and wires.

 

I'm going to say you probably broke one or more of the vacuum lines that attach at the back of the intake when you were back there replacing your oil pressure sending unit.

 

Vaccume leak.

I messed up when taking my 90/90 FAST and going back to a LS6, I did not connect one of the HVAC lines and pinched it between the cyl head and intake. Lost HVAC controls, vac leak, loss of power, overly rich etc etc.

 

The gas mileage was shot before replacing the PCV valve and oil pressure sensor. I noticed a long trail of liquid coming from my car on the way home today but I couldn't really get a smell. Could the exhaust be leaking and if so, how do I diagnose that?

 

My car used to misfire and leak out of the exhaust. It was caused by a broken valve spring.

 

Yah. I vote valve spring.