Random throttle surge when idling through parking lot??

[jmac219]

I did some searching without any luck. I have a 4.2 02 Envoy with 180K on it. Today as I was idling through a parking lot the truck randomly acted like I gave the throttle a pretty good tap and the truck surged forward quite a bit. I actually almost hit a parked car!

It kept doing it every few seconds or so as I kept idling. I hit the brakes then it just completely stalled after I came to a stop. I started it right back up and it was completely fine for the rest of the day. I have noticed in the past few months when sitting at a stop sign or light it would just randomly stall out with no warning. It would start back up just fine and be fine for a few weeks.

I've already cleaned the throttle body a few months ago, new AC Delco spark plugs & fuel filter. I'm not sure what it could be! The only CEL I have is P0340 "Camshaft position sensor "A" circuit (bank 1 or single sensor) However that code has been with the truck for the past 2 years & was replaced but the code came back very shortly after.

 

[Mooseman]

Well it should be fixed properly. Could be a broken wire. It's rather vital.

 

[Maverick]

If you cleaned the throttle body, did you reset the PCM by disconnecting the battery or pulling the PCMB fuse under the hood?

Sounds to me that the truck is surging because the AC clutch is cycling and the throttle body hasnt learned the correct positioning for when the AC is on. I know the AC clutch cycles on the Auto Climate control, not sure about the manual control.