2000 V-6 Misses On Deceleration

Sister's van misses, ONLY on deceleration. It'll run fine for a couple weeks, miss for a while then back to missing again.

They've had it to a couple mechanics, nothing shows on the computer. Changed plugs, wires, 3 distributor caps and a few parts I can't remember just now.

On a recent trip from MN to Florida, it would run fine for hundreds of miles, miss for a while then run fine again. Any ideas? It has a V-6 Vortex.

Thanks,

O'Riley

what are the smyptoms? don't get it , on deceleration only how do you know its missing? live data on a brand new gm car will show misfire on deceleration and not log it to history. missfire monitor is real sensitive on these cars to protect the cat. if it was having a misfire it should log a code.post back specific drivability problem.

Talked to her husband, has rebuilt engines for a living, 25+ years, he has no idea.

More info: Computer says: random misfire.

Parts replaced: crank sensor, cam sensor, injectors and fuel filter. Reads 60# of fuel pressure.

When the engine is cold, accelerating it acts like you turn the key on-off-on-off.

Deceleration: going up a hill it runs fine, cresting the hill you feel a chug-chug like sensation as the cruise control throttles down. Can't hear it misfire, just feel it.

Hope that makes sense, that's what they said.

O'Riley

they have alot of time and money in it. a set of factory wires (seen cheap parts store wires create as many problems as they solve) ac platinum plugs and a cap and rotor is where i would go next.