My car has been having some issues. Run's ok on startup, but the longer it runs the worse it gets. If it runs for like 20 minutes, and I give it gas, it will backfire through the intake making the "Pop" sound. It will sound flooded and I'll have to give it gas to keep it running while it pops and backfires, then eventually will clear up and be driveable, but not good. Throttle response is weak, etc...

I'm not sure where to check. I just pulled all the plugs and they all look good, barely any wear. I was expecting them to be black because I had assumed the car was running rich.

I'm not sure where to look, I'm really confused.

What else can cause this? There is no SES light. Mods in sig.

Opti is new OEM unit.

 

Un plug an O2 and see if the problem disappears.

 

Did it start after installing the Opti? Or after any other work on the car?

Rich

 

No, just kinda crept up over the past couple weeks.

I replaced the opti because everytime it would rain or be wet from humidity outside the car wouldn't start for a couple days until it dried out. That problem is fixed, and the car ran great for for a couple months. This just started getting bad over the past few weeks.

I'm thinking fuel pump, but I've also thought about the o2's.

 

Tried unplugging each one and it made the problem worse. Car wouldn't go over 3k at WOT.

 

If 02's were the problem generally the car would run fine until going into closed loop. Get yourself a fuel pressure gauge at any auto parts store and check to see what it's doing. Are you sure your plug wires are all in tact and not burnt?