My Chevy Venture van was doing something similar. Turned out to be a vacuum leak on the little " t" that comes off the PCV valve line. Its hidden under the triangular shaped throttle bracket. I could hear the air hissing from it. I undid the two bolts that hold the bracket down (10mm) and when I pulled the " t" out, the motor really went haywire! Throttling up and down like mad until just stalling out 10 secs later. What I did: ok this is kinda redneckish, but I cut a small piece of washing machine supply line hose (smaller than garden hose). The size just happened to be perfect and I slid it on the end of the " t" and put it back in its hole. Presto! No more vaccuum leak and my van is purring like a kitten now. Probly helpful to mention that after I put the throttle bracket on I hit the triangular part that covers the " t" with a hammer until it pressed down hard enough on the " t" to seal the tiny air leak it was still letting through. Hope this helps someone- sorry about the non-technical nature of this post, but it may give someone a $0 fix for their engine chugging at idle problem.
Monday, March 22nd, 2010 AT 6:14 PM