2007 dodge Dakota 4.7 v8 flex is throwing codes p1128 and p1129. I know what they mean. Truck is also running like crap, start it up it dies after 2 or 3 mins, press brake pedal or gas it dies almost immediately. Shifts from 1st to 2nd it dies...had to limp home for 3 miles. Was told by mechanic it was computer going out. Computer has a temp of 120 F. Is it the pcm? I just don't want to buy one if it is not.

 

P1128:
- Fuel delivery system
- Manifold Absolute Pressure (MAP) sensor or wiring connectors
- O2 sensor wiring or connectors
- Engine mechanical system
- Faulty Powertrain Control Module (PCM)

 

It was put on diagnosics 2 times everything was functioning as it should..but I have now noticed that when it gets to about 195 degrees on the gauge, my engine dies..I'm think ing thermostat But why does it also buck when it is hot

 

I agree with jkeaton mostly. Our trucks have a built in filter that is non replaceable unless you replace the fuel pump but I would only replace it if it is failing. Did you get some bad fuel/water in your fuel somewhere? Have you checked the fuel pressure? Are there any other codes? Once the fuel side is diagnosed, I would definitely go for the MAP. That would cause the truck to act as you said especially when shifting from park to a gear which changes the vacuum pressure affecting the MAP readings. These are the places and items I would start with.

Its not your thermostat. I could guarantee that. The thermostat is just a mechanical type part that opens and closes with the temperature of your coolant. It has no bearing on anything electrical. 195 is the operating temperature and the temperature your stock thermostat opens. That's normal temp.

 

Does it run well up until it gets to that temp and then it dies or does it run poorly all the time? I had a 88 Dodge Shadow with a bad coolant temp sensor. It would run pretty good until it warmed up and then the sensor went open above a certain engine temp. Caused all sorts of havoc. Stalling, ran rich as heck, etc...

 

Then on to this just like jkeaton listed above... good stuff, rodslinger!

 

I replaced computer 700.00, flashed 115.00, thermostat 22.00, map sensor 45.00, engine coolant sensor 25.00, A week ago. I replaced the catalytic converters and oxygen sensors 6 months ago. Replaceing the computer seemed to help with the stalling, but I still have the codes p1128 and p1129. The truck still bucks every now and again with the temp at normal operating level.

 

Just an update. Firestone checked the fuel pressure the other day, and said that it was good. Spark plugs replaced with NGK v power 2 weeks ago. Oil changed 2 weeks ago with valvoline high mileage synblend 5w 20 and purolater oil filter. Truck has 120,855 miles. Most of the bucking is when going up hill or hard accelerating.

 

The fuel pressure test needs to be done while driving to make sure. Also take a fuel sample. Check your air filter. I've seen them sucked in before..lol.


If you're setting the same codes for both banks, you have to look to something that effects both banks. In which case, you're back to fuel, timing, vacuum.

 

i now notice that if i try a little night driving, when it goes to start bucking, the headlights also flicker but dont go out.