Brought my '90 V6 cross country. Went to get a CA smog, it failed on 2500 rpm CO. Immediately went to DMV to get a temp tag, and it barely made it back.

Now when the engine hits 160* or 180*, it immediately loses all power and begins missing. If you depress the accelerator more than a hair, it stumbles and will backfire if you press hard enough. It has just enough power to hit 20 mph on perfectly flat ground after 30 seconds.

I work on a military base, and it's at the shop there. It runs great cold, but there's no way it would make it the 15-20 miles into town.

I started with a set of plugs. New wires. New cap and rotor. Other than a slight oil leak on one valve cover, all looked great. Injector cleaner in tank. Fuel treatment. Tank is full. New oil, new air filter, new fuel filter.

Mechanic found a hole in the radiator, thought that air cavity was causing temp misreading and ECM was dumping fuel to warn engine. Replaced, pressure tested all hoses good. Mechanic tossed on new EGR, but says it had no effect so took it back off. Replaced factory O2 sensor (oops!).

He's out of ideas. I'm almost positive it's now fuel flow. Fuel pump less than 1 year old / 5k mi. Have not had time to check pressure at rail, but the backfiring makes me doubt it.

Only out $290 for radiator and O2, including labor. Plus cost of tuneup parts.

Need tr

 

*not fuel flow

Need ideas for things to troubleshoot. Have full access to bays, lifts, most of the shops tools. Can get free mechanic assistance. Or hire mechanics at reduced hourly rate... but not idea where to go now.

 

I seem to be having very similar problems, and have been perusing these boards for months now. Mine stalls when it gets to the same temps and especially after driving for about 45min to an hour. Running around town under an hour it never poses a problem. When the temp gauge sneaks past 180 it stalls and will not restart, acting like it is flooded or not getting fuel. Schraeder valve has fuel coming out. If I let it sit for about 15min, it will start right back up and get me going a while till the temp hits 180 again.

So far, in reading all the advice, I have replaced:
plugs, wires, cap, rotor, icm, iac, tps, maf sensor, fuel pump relay, maf relays, egr, fuel reg, injectors, and O2 sensor.

Trying to get to the G15 in Atlanta tonight......HELP!!!!! It's an 8 hour drive, I hate to have to do it in 1hr spurts!!