Elusive Heat Related Engine Problem....
 

...only happens on hot afternoons, and very infrequently (3 times since May) driving I-95 home from work at 70 MPH with A/C on. Car is 2001 Civic EX coupe.

....car will 'stutter' and loose power. Doesn't shut down, but runs rough with very little power..dangerous if it happens when I'm in the left or center lane. When I pull over, there is white smoke coming out under the front wheel wells. I shut the car off, open the hood, check the oil (OK), and let it sit for about 5 minutes. Then, I can start the car up and, with the A/C OFF, I continue to drive another 10-15 minutes home without problems. Never happens in the morning on drive to work, with A/C OFF. Hasn't happend when driving in town at lower speed with A/C ON.

Happened again yesterday (9/30). Smoke is coming from catalytic converter. Could it be a fuel problem, perhaps related to fuel pressure ? I read about that solenoid located on that evaporator canister causing problems when fuel vapors expand. Anyway, CE light came on, but was off this morning all the way to work. Again, this seems to be a hot weather issue and with A/C ON.

Smoke from under the hood is never OK. Need to find where it was coming from. Did the smoke smell like burnt rubber (like the compressor seized and the belt slipped) or antifreeze (engine overheated), or what?

Closer to burned rubber than anti-freeze or oil. Seems to be coming from the back side of the block. But the A/C is working fine...I've been driving around all day today in-town with the A/C on..nice and cold. I used it the past few days on the way home from work, too; no problems.

Check that the belt is tight. It may need replacing if it has been slipping and burning. If this happens again on the road, immediately turn the A/C off. Also if it happens again you should take the belt off and spin all the pulleys by hand to see if any bearings are going bad.

Follow up:

It seems that the aftermarket gas cap that I've been using for two or three years may have been the problem. I had a CHECK ENGINE light on , forst intermittently and then solid, for several months and suspected the gas cap
was not holding pressure. The CE light went out within a day of replacing the gas cap with a OEM Honda cap. Since then, I have driven at highway speeds in hot Florida afternoon temps with no problems with the AC or any other engine related problems or shut-downs. At this point, I'm attributing the problem I described as due to incorect fuel pressure due to a faulty gas cap.
Lesson learned: Used ONLY Honda gas cap .

What caused the smoke and heat???? Certainly that was not from a bad seal at the gas cap?

I have no idea ! Since there has been no re-occurance of the problem , I may never know. Everything is now working great, including A/C. Could a lean fuel mixture due to poor fuel pressure cause any overheating ? The temp guage always read normal.

Just had a similar smoking burnt plastic smell issue when I initially started up my '01 after replacing the head gasket. Turned out to be some oil and random schmootz on the exhaust manifold. I panicked because it smelled like a wire or belt burning, but I pulled the heat shield off the exhaust and found the source of the smoke there. Bet yours was something similar.

Happened again yesterday (9/30). Smoke is coming from catalytic converter. Could it be a fuel problem, perhaps related to fuel pressure ? I read about that solenoid located on that evaporator canister causing problems when fuel vapors expand. Anyway, CE light came on, but was off this morning all the way to work. Again, this seems to be a hot weather issue and with A/C ON.

The draw from the compressor probably causes the motor to run just a tad hotter, which causes whatever material is trapped against a hot part of the engine or exhaust to start smoking again. I (not being a mechanic, just a guy with a box of wrenches and a book) am a big fan of ruling out simple stuff first. Pull the heat shield off your exhaust manifold. Start the car and let it run til it reaches operating temp with the A/C on and get your head in there and look for smoke and sniff around for the source. It could be a wire, a broken plastic clip, some residue from trans fluid, oil, fuel injector cleaner, grease, just about anything that is just stuck to or pressed against a hot engine or exhaust component. If you find nothing then, start checking more complicated stuff, like the catalytic converter.