Hello all. I need some advice from some of the fuel injection gurus I have a 2003 Dakota quad cab with a magnum 3.9. About 50% of the starts are normal, but the other 50% the engine will crank for 3-5 seconds and sputter to a start, then slowly increase in speed and smooth out until it hits idle speed, all the time reeking of unburned gas. This is usually accompanied by a blast of smoke out the exhaust too. Once it reaches idle, it's OK. I suspect I have an intermittant sensor, but don't know enough about the fuel injection system to know which one(s). I have cleaned the K&N air filter, run some injector cleaner through, and even replaced the IAC valve on spec. Still no improvement. Anyone have any ideas?
Thanks in advance.

 

sounds like a bad map sesor to me man.

 

Thanks for the advice. MAP sensors run around $40 on ebay, so I'll order one and give it a try. I read somewhere about resetting the ECU after a sensor change, do I just D/C the battery for 5 minutes or so to clear the memory, or is there a procedure?

 

As far as clearing the ecu ive been told to d/c the battery and hold the key in the start or run position for about 10 seconds draining any power in it

 

yea bigreed has it right. good luck hope it helps ya

 

Cool. Thanks for the help. I just ordered a MAP sensor from ebay. I'll post a reply with the results. Thanks again guys.

 

Well, I got the MAP sensor installed, problem remains. I just found a post on how to check the codes, did that, and found P032, P037, and P132, which all refer to O2 sensors. Maybe my truck's actually trying to talk to me. I'm a bit unclear, however, as to how many O2 sensors there are (I figure at 260K I may as well replace them all ) Is there 4 in total, left and right upstream and left and right downstream? Any help would be appreciated. Thanks in advance.

 

Sorry, just checked my notes... the actual codes I pulled are P0031, P0037, and P0132. They refer to O2 sensors at Bank 1, Sensor 1, and Bank 1, Sensor 2. How do I determine which sensors to replace? Thanks.