Engine/Transmission (1998.5 - 2002) A/C on = truck runs like crap

[RJPotts]

Alright,

Yesterday I had the A/C on (2nd line) it was all good for about 10 minutes/2 miles (traffic sucks). I started going at a light and it made a LOUD pop (like the exhaust was plugged and it blew out) then it ran like it was bone stock, wouldn't get out of its own way, stumbling, "missing" (not bad, but noticable), then is started popping again.

I turned off the A/C and the popping stopped but it still ran like crap. Got home, NO CODES at all, CEL was NOT on. Let it cool down for a while, went and got some fuel and it seemed fine.

Later on I was driving down the interstate and all was good, then suddenly it started running like garbage again.

Its done this once before and both times its happened when the A/C was on and it was really hot out, NEVER before or for any other reason. (First time I got a "Low Boost for conditions" or something like that code, MAP sensor)

We stopped at Auto Zone and I got some electrical parts cleaner, cleaned MAP sensor and all the EZ connections, problem went away.

So I know what the problem is, the question is, why does it ONLY happen when the A/C is on??????

Thanks in advance,

-R. J.

Sorry for the really long post

 

[nps]

Alright,

So I know what the problem is, the question is, why does it ONLY happen when the A/C is on??????

Thanks in advance,

-R. J.

Sorry for the really long post

I would speculate that it is heat related. With the AC on, you are putting alot more heat under the hood by way of the condensor. The fan pulls that heat in, and in slow traffic the temps build.



I'd recommend you look to the ECM connectors and grounding also.



Finally the VP may be getting ready to go. Blue Chip has a writeup on their website about the VP being heat sensitive and the electronics on top of the pump being particularly susceptible to heat-related flakiness.

 

[RJPotts]

Well that sucks. I assumed that it had something to do with the extra heat, but then I decided that wasn't the reason because it always fixes itself when I unplug the MAP sensor plug and clean it.

Maybe I'll get some electric grease and fill the plug and see if that makes a difference. Or even better, maybe the VP will go, I'm still under warranty and I'd like a new one to start out with once the warranty is up (about 12,000 more miles)

Thanks,

R. J.

Any more opinions, anyone?????