Good morning everyone. So I've had my 2001 Durango (4.7L) for coming up on 4 years now and I'm having an issue that we just can't figure out. Any help or suggestions would be appreciated. So here's some background.

I was driving home from work one evening, doing about 35mph. All of a sudden the engine just started reeving by itself picking up speed (nothing crazy) and started to have a weird feel to it. When we got to the first stop light the engine was almost stalling, the engine was jerking, erratic idle and every so often a pop sound would come from underneath. The most concerning part was the engine had no power. It would sound normal when taking off, but it felt like I was granny clutching it (half engaged making it move at half speed). I stopped and put gas in it and had problems getting it to start back up, it probably took a good 60 seconds. Once I got it home we checked everything we could and just decided to try again in the day light. The next morning I drove it to work and it did the same, so I decided to park it at work, which is where it sits now.

I just finished testing it and reading/resetting codes which boggled my mind more. The engine when revved up, will not go above 3k RPM's. It will hit just below 3k RPM's and just stop, it reminds me a rev limiter.


Codes: P0320 & P1281

I've done some reading into these codes and see that it could be triggered by the crank shaft position sensor, which was replaced about a year ago. The entire cooling system has been replaced (hoses, radiator, water pump, cap and thermostat).

Here are a few videos and screenshots.

Codes:



Engine Idle:



Video of revving engine peaking below 3000 RPM:

 

Ondemand shows:
1281
Engine coolant temp monitored with engine running. DTC will set PCM memory when PCM senses engine coolant temp does not reach 176° while driving for 20 min. after start. Possible causes: faulty thermostat, cooling system concern.

test
Check coolant level, start engine and allow to idle. using scan tool, set engine speed to 1500rpm and allow engine to warm for 10-15min. Using scan tool in sensors mode, read ENG COOLANT TEMP DEG value during warm up. Ensure temp value increases smoothly. If scan tool does not read at least 176°, check thermostat and coolant system. If scan tool reads at least 176°, no problem indicated at this time.

0320 No crank ref. signal at PCM
Possible causes:
Intermittent CKP or CMP singal, or wiring harness concern
5 volt supply circuit open, shorted to ground or battery voltage
CKP sensor signal circuit open, shorted to ground, 5 volt supply circuit or battery
CKP sensor ground circuit open
PCM 5 volt supply fault
PCM CKP sensor signal fault
defective tone wheel
faulty CKP sensor

A lot of testing for this one.

I would check 1281 first and even replace the thermostat. Then on to 0320 checking wires harness and the wires to the CKP, check voltage to CKP, check ground connections.

 

What does the temp gauge say?

 

After driving and engine idling for about 20 minutes, it was at 152.6.

 

only reving to 3k rpm sounds like limp mode, figure out why its in limp mode and you find your problem.

reading what youv posted i would start with the crank position sensor, clear all codes/reset PCM and go from there. good luck

 

It ended up being the crankshaft position sensor, shocked that stupid thing made it run so bad. Thanks everyone.

 

Actually a CPS usually quits dead, and you're parked. Your ability to limp along was lucky.