AC on, mash gas, car might stall?

[pagluy]

So I hardly ever run with the AC on, I just enjoy the windows down too much. I go on a trip to Michigan a few weeks ago with a couple people, so I run the air a lot. Hot rod it around all weekend on that trip, no problems.

I should note here that I have a Xcal 3 and custom tune, I had been running at -0.1 spark all weekend, and on the way home I adjusted it back to 0.0 (normal). Don't know if this could have any effect but figured it was worth mentioning.

On the way home I get on the highway and floor it to get up to speed (was going about 35 when I did this), car starts to go and then dies, ETC failsafe beep and warning comes on, pull the car over shut it off and start it again and it comes on right away. Drive home rest of way, no issues.

Drive for a couple weeks, mostly non-AC and have no issues. Then one day I'm getting on the freeway again, not accelerating hard this time, but I step on it some to get up to speed, AC is on, and ETC failsafe comes on again, but this time car did not completely die, still had power but it felt reduced. Pulled over shut off back on, no problems again.

That was about 3 weeks ago, and I haven't had the AC running at all and I've been mashing the gas quite a bit on on-ramps and all that to see if problem will happen again.

So I think this failure is related to the AC being on, but I have no idea why that would be. I figured it could be my electronic throttlebody, maybe. Am waiting to see if it will ever stall w/AC off.

Any ideas on what could be causing this?

03 V8, Xcal3, K&N intake on my car.

 

[milehighmikey]

It sounds to me that you've got a harness chafed somewhere and when your engine moves on its engine mounts, it shorts a line or opens a line, leading to the false failsafe. It also sounds vaguely familiar as a possible connector corrosion issue with the actual CHT sensor. (cylinder head temperature)

The system should compensate for a wide open throttle action by temporarily suspending the A/C clutch, but still, a running engine should not be stalled by a compressor engagement.

 

[SoonerLS]

One source of a false ETC FAILSAFE warning is a failing COP, particularly the one on cylinder #4. One of the failure modes creates RF interference, and cylinder #4 is close enough to the PCM to induce the false error.

 

[pagluy]

Thanks for the replies guys. I think I might have a coil starting to go, maybe that explains it.