I have a 2000 4.7 V8 manual Just picked up this truck used about 3 weeks ago. It ran like a top for a week and has been in and out the shop since then! The original issue was the check engine light came on and after a few miles of riving started not wanting to go anywhere. IE when I hit the gas it does nothing! Engine idols fine and seemed to spit and sputter. shut the truck off turn it back on and it runs like it should for a few moments then hit the gas and it falls flat on its face again. Took it to my local shop who found three bad coils ... replaced those and all new spark plugs. Got the truck back out drove it perfectly for about 30 miles and Bling check engine light on and same problem. Took it back and this time both o2 sensors have been replaced. The error code showed low voltage on the down stream o2 sensor and high voltage on upstream o2 sensor. got the truck back this morning drove to the store and, wouldnt you know it check engine light and (for lack of a better description) hit the gas and nothing! but the truck still running! Idols Great, the issue is seemingly getting better but still exists. We have also ran a fuel pressure gauge and the pressure is to speks! Drained the tank and put fresh fuel in, ran fuel injector and high octane through her. And now my beautiful truck is sitting at the shop with the same issues! My mechanic is suggesting replacing the fuel injectors, and possibly the PCM! PLEASE FOR THE LOVE OF ALL THINGS HOLY! ANYONE HAVE IDEAS I CAN THROW AT THIS WRENCH MONKEY? SO I CAN GET THIS ISSUE FIXED?

 

Wow, doesn't sound like your mechanic is very qualified. Anyone can just throw new parts at a motor and see what sticks, but not very efficiently. Three simultaneous coil failures is unlikely and if you already paid for the new ones I would definitely want the old ones to keep as I am not convinced they are bad at all. If he hasn't already he should be back probing some of the sensors like the Throttle position sensor and Mass air pressure sensor just to make sure they are operating properly. A mechanic should know to do this to verify they are functioning before buying new ones. The PCM can be sent out to be verified if necessary before replacement also, it is rare for the PCM to be bad. As far as replacing the injectors it doesn't sound to me like something that would solve your problem but definitely will lighten your wallet by a few hundred bucks. You did not say whether he dropped the tank to check the fuel filter but there is a fuel filter in the tank that is only serviceable by dropping the tank but the labor will cost you. I would start with the sensors as they can be eliminated as suspects without costing you a lot. You cannot alway just count on the engine light codes as sometimes they are a symptom of another underlying problem. Good luck.

 

I moved your thread into the general forum. It should have more views.

I agree with dxloat, your mechanic sounds "inexperienced" at best. He's just chasing parts.

Try this, pull the connectors on the PCM, on the passenger side inner fender. Look for any fluid in them - ANY! A common problem is the power steering pressure switch leaks and pushes fluid into the wiring harness. It often causes O2 sensor problems.

It's unlikely the for fuel injectors to be "intermittent" especially ALL of them at once.

Does he have the capability of looking at "live data?" This should help narrow down what's happening to the truck.

Keep us posted.

 

One of the sensors I'd check early on is crank position sensor. I just posted about my experience with one of those on my 3.9. Truck would run like a top and suddenly barely run at all.

 

ran the suggestions you guys threw at me by my mechanic! HE was not so happy with my suggesting he look into these things before he starts charging me again! The Dakota is currently sitting in my driveway ... the error code persisted p0132 high voltage on upstream o2 SO i disconected the damn thing and guess what? truck runs like a top! no issues with stumbling at all ... the mechanic says its NOT the o2 sensor "I JUST REPLACED IT" his suggestion its a bad PCM! Either way im not noticing much difference in fuel economy and its a dream to drive! Any thoughts on the PCM being bad? and why would the PCM be bad on only the signal to the ONE o2 sensor?

 

I wonder what brand O2's he used...agree, doesn't sound too intelligent...at least with computer controlled vehicles.

 

hears a WILD idea. get some marvel mystery oil. put it in the gas. 4 oz in 10 gal. it should clean the injectors. and lube the valves, and rings. makes my engine start faster.

 

still sounds like an o2 sensor to me. the fact that you disconnected it and ur truck runs good makes me think it is bad. someone else who knows these trucks better can answer but i would guess if the pcm doesn't see the o2 sensor plugged in it would resort to a factory fuel table(limp mode) rather than using the o2 sensor to figure out your a/f ratios.