Recently my car hasn't been running very well once warmed up. When cold it runs perfectly and once warmed up runs perfectly half the time. The other half it sputters under load and when coming to a spot the rpms drop to almost stalling or stalling. Then the car won't start for a while. If I turn the engine off after a long drive, it'll start right back up, so the hot start problem is when it stalls on its own.

Spark plug wires?

Suggestions?

 

start with plugs and wires. verify the voltage form the o2 sensor is correct.

 

Yup, at least look at the plugs.



What kind of fuel mods do you have?

 

Walbro 190 HP Fuel Pump and BEGI AFPR

These have been on the car for a few years, no problem until now

 

you could also have a fuel injector hanging open and dumping fuel into the cylinder, you could take each one out and test them individually by hooking them to a 12v source and grounding the other side and listen for the click

 

bad coil packs act up as they get hot

 

What year is your car? Do you have a WB02 sensor?

Can you give us the full specs of your car?

 

WB not hooked up yet

1992 with Greddy Turbo, Intercooler, BEGI, Bipes, BOV, MBC, DP Back Exhaust, 8psi

Have had this setup for over 2 years running perfectly

Just recently started having slight problems

 

Dang no WB.. I was wondering if you were running richer than normal that might indicate an injector sticking..

 

pull the vacuum line off your FPR and see if there is any fuel or fuel smell in the vacuum hose. this sounds similar to a diaphragm leak.

 

Changed the Water Thermosensor today, after a few drives to work next week, I'll know if the problem is solved

 

Pull apart the AFM, clean the brushes and contacts and increase the pressure on the brushes.

 

i had a problem like that before. ran great when first started, but if i turned the car off and started it again, it would miss badly. i had autozone wires, i would exchange them, it would be ok for a week or two then start doing it again. i put on some NGK plug wires and have not had the problem come again yet.

 

Confirmed, after two long enough drives that would normally cause problems, car is running perfect.