Alright here is the problem ( on 1994 dodge ram 1500 5.2L). About 3 weeks ago my truck suddenly, liek you press on the gas and it will die. Started with pulsation and heavy bogging then turned into crap idle and cant rev.

What I know, there is spark, fuel pressure is in specs, all sensor are in specs(according to scan tool). Runs better when O2 sensor is unplugged but still crappy, able to atleast rev but doesnt burn all the fuel (black smoke). Timing is advanced 17 degrees(once again according to scan tool). Timing chain is good, already checked that. checked a lot, if u listed things off ill be able to tell u if we checked or not.

what we have replaced:
MAP sensor, camshaft position sensor, throttle position sensor, O2 is only year old, Crankshaft position sensor replaced in bout july 08, mayeb few others cant think right now.

We have tried so much to figure it out and can't seem to get it, if anyone has any ideas on what to check ill be happen to next chance try it and repost.

 

I know of one poster on here who's truck was stalling like yours, and I believe he fixed it by having the dealer purge the fuel system and clean the fuel rail and injectors. The only other sensor that you haven't replaced is the idle air control valve (IAC).

 

if its running overly rich with black smoke and maybe smell of gas, i'd suspect a bad injector dumping gas. that should show up as a wet, fouled plug. how do the plugs look ?

how about clogged cat? that can prevent rev.

 

IAC just provides an idle bypass around the closed throttle plate. once you crack open the throttle, its out of play except for the possibility of it being a vacuum leak.

 

When i checked the plugs they just had the black look liek burnt oil(from when i was doing a wet compression test), then i checked the IAC and that is working fine. Also i do know that for some reason when the O2 sensor is plugged in it changes the pluse width to, highest i saw), was 10 ms and the sensor kept reading really low voltage at O2 sensor. then when unplugged goes to stock settings and has pluse width of 1.82 but still runs liek crap as i said before.

 

dhvaughan, I think he's running rich after unplugging the O2 and going into open loop start up mode. With it plugged in, sounds like he's leaning out.

 

It truely is frustrating for this to happen, im all out of ideas on what to do. liek My dad and me are down to cleaning connectors and cleaning vaccum ports, and just tedious work

 

Can your scan tool record a strip for your O2 readings? I know of a particular instance where someone was trying to TS a problem and found that his O2 was only reading 0V to +5 volts when it should have been ranging between +5 and -5. It turned out to be a badly grounded exhaust system. Hope that helps.

 

i'll look into it tommorw

 

You said you replaced the o2 sensor, but which one did you replace? I believe there are 3 of them.