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Let me preface with saying I did search the forums but couldn't find my exact problem.

My 99 PGV has an issue only when I come to a stop. As I'm stopping (maybe still going 5 mph) the engine revs to about 2500-3000 rpms then shudders and lurches once or twice, rpms dip really low, then come back to normal when the van finally stops. The van has stalled once or twice before as a result of the rpms dipping.

I can avoid this problem by shifting into neutral as I come to a stop, but when I shift into drive again from neutral the van rpms dip low again before I get a chance to accelerate.

I've been told to replace the IAC, does that make sense? The van doesn't miss at all in neutral or park OR when driving, just when coming to a stop.

Thanks for all the help!
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That goes without saying. Anyone who "cleans?" a TB and does not service and reset the IAC should have every tool they own taken from them forever
Okay, for those of us who don't understand some of these abbreviations is there a post for them and where is it:ask_wsign What is an IAC:ask_wsign, no you can't have my tools, some of us are just becoming familiar with the computer run vehicles after being away from it for 20 years, bit that doesn't mean we can't turn a wrench. :bcyclop:
 

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TB = Throttle Body
IAC = Idle Air Control valve

The IAC is on the TB and gums up with carbon. When you have carbon deposits in there, it can stop the IAC from working properly, making the car idle crazy. When they go bad they do the same thing, but cleaning it is free and the first thing you should do.
 

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TB = Throttle Body
IAC = Idle Air Control valve

The IAC is on the TB and gums up with carbon. When you have carbon deposits in there, it can stop the IAC from working properly, making the car idle crazy. When they go bad they do the same thing, but cleaning it is free and the first thing you should do.
Okay so how do you reset the IAC:ask_wsign
 

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Hmm. Engine apparently idles fine when the transmission isn't engaged. Hmm.

ShortTom - Does the engine idle fine when not in gear with the A/C on and you rev the rpms up then release the pedal? If it does idle fine then I would lean away from the IAC valve causing your problem. When you turn on the A/C the Powertrain Control Module (PCM) bumps the idle RPM up to overcome the added load of the A/C. The PCM opens the IAC valve to accomplish this. If your idle is fine then this yet another an indication the IAC valve is doing it's job.
 
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