I have an '02 Ram van 1500 V6 92K miles. Was driving one day & suddenly got nothing when I hit the gas pedal. New plugs, cap, rotor, wires, fuel pump, PCV valve, TPS, Distributor, Crank angle sensor..... K&N filter (clean), IAC cleaned, throttle body cleaned, no oil/moisture in intake, ECM checks ok at dealer, no error codes, fule press check ok (50 psi), disconnected O2 sensors (no change), no exhaust restriction (disconnected exhaust pipes at manifold to check)... running out of options.... any ideas/expert advice? I need this thing to get to work.. backlogged for 2 weeks now.

 

The timing chain could've jumped a tooth or two. Have you done a compression test?

 

Compression ok, popping from intake occurs on random stall outs. Also the engine will idle itself to a stall sometimes, followed with high vacuum suction from throttle body.....

 

Then you could just have a crank sensor that is on the fritz and causing the timing to retard, or at least not advance.

Regarding the new cap, it has to be one with brass contacts, the ones with aluminum contacts don't work well in these engines.

 

The crank angle sensor is 2 days new . I will have to check on the cap contact material tomorrow.... however, I have been running with it for about a month now.....

 

Maybe dirty, stuck injectors? Maybe a bottle of techron?
How about vaccum leaks? Water in the tank?

A bad MAP sensor can cause those symptoms too.

Just some ideas if you already haven't thought of them.

 

I use Injector cleaner regularly, no vacuum leaks detected, no water in tank.... would a defective MAP sensor not show up in the codes? The scanner comes up with a pass on all sensors.

 

In theory it should. I just had a similar problem and it ended up being the o2 sensor. No codes at all, but it caused such drivability problems I couldn't believe it never through a code. I thought computers were supposed to make things easier. I guess sometimes they through a code and sometimes they don't...maybe it's a flaw in the computer design or firmware as I tried a junk yard computer and nothing changed.
From what I understand is the computer controlling the engine is in "open loop" until the o2 sensor heats up. After that it's in "closed loop" I'm not sure what other sensors are in play during "open loop" if any.
I think the codes are just supposed to get you in the ballpark of what's really wrong.
After my problem, I feel for ya. These types of problems are hard to pin down.

 

This site may give you some insight.

http://www.aa1car.com/library/1999/cm69910.htm


Another thought: When you unplugged the pre-cat o2 sensor, did the check engine light come on? If it didn't I would suspect the computer. I'm no expert though.

 

I gave the fixing a rest and rented a Chevy (I can hear the boooo-ing from here), to finish up the work I have left. I will tackle it again when I get a chance.. Gotta juggle 2 jobs at the moment. I must admit though that the van behaved a bit better, though temporarily, with the O2 sensors disconnected. It's a bit rough to keep spending on these sensors in hope of correcting the issue.. already in about $500. Anyone ever heard of a 24 hr ECM discharge (disconnect the battery) to clean memory?