My 4.7 has 230k problem free miles, but at about 7 months ago I was using it, cut it off and when I went to start it back up it was running very rough, sounding like on 4 cylinders, and speedometer is stuck at the max 120MPH

Finally got around to working on it and so far I have pulled the valve covers and no spit "rockers". Fuel pressure within spec's. Can hear with stethoscope that each injector is pulsing. Each coil is getting spark. No check engine light or codes. Decided to throw a crank shaft position sensor at it. Camshaft position sensor is fairly new (about 4 months on it when the truck started acting up).

Anyone have any ideas here.

My thoughts are ECM or jumped timing.

Thanks in advance!

 

Forgot to add

Truck is a 2002, automatic, 4wd.

 

Make sure you're using Mopar sensors.

 

Before throwing over $100 in Mopar sensors at it let me run this by you.

This problem started all of a sudden, replaced the crankshaft position sensor with a standard products and zero change.
The camshaft position sensor was replaced 4ish months before with a standard products, changed it again after this and still no change.

One would think that it should have some kinda change help some, may not be accurate as the Mopar. I mean the standard products camshaft sensor worked fine for months.

Looking forward to your reply

 

That's the way these cheap sensors go.

I installed a cheap air temp sensor 5 months later rough running problem's tested it and it was bad burned up installed my old sensor no more problems.
The only reason I replaced the oem one was I felt it was time not that it was bad.

Cheap sensors are a real problem with our Dakotas

 

have you ran codes?

 

no codes

 

This may be the problem

4. Vehicle loses power

Today's cars and trucks have electronic fuel injection, which is controlled by the onboard computer. The EFI supplies fuel to the engine based on input from multiple sensors; one of which is the speedometer sensor. If you notice that your car starts to lose power; especially when you apply pressure to the throttle, this might be caused by a damaged or malfunctioning speedometer sensor. This problem could be potentially harmful to other mechanical components on your vehicle, so don't ignore the issue. Contact a certified mechanic as soon as possible to determine what is causing this issue.

As you can see, the speedometer sensor impacts the operation of multiple components that allows you to efficiently operate your car or truck. Anytime you experience any of the above warning signs, contact a professional mechanic to properly diagnose and repair the issue.

 

Started it and moved it the other day, now the speedo works like it should, still seems like its on 3 or 4 cylinders.

Going to try to get Mopar sensors in a week or so, unfortunately I feel its peeing into the wind but its worth a shot, going to make another post about checking out a few other things too while I'm messing with it

 

That's the spirit... Rome wasn't built in a day.