05 Dodge Dakota, I’ve had this thing for 4 months now. The Check engine light came on 2 1/2 week after I bought it. I get a P0300 almost every time (a couple of times I got a P0303 and P0307). 75% of the time it happens when I leave work. Usually as I’m leaving my parking spot. I go home clear the code and it drives fine the rest of the day. The other 25% is the Morning as I’m leave for work.

I’ve change the spark plugs, I’ve put 3 bottles of Lusca fuel inj. cleaner in it. The time I got the P0303 code I swapped the coil pack from cylender 3 to 1 But, I only get P0300s now.

These codes can be caused from a dirty/defective Mass Air Flow sensor.

You might try first getting an aersol MAF sensor cleaner and clean the hot wire of the MAF sensor to see if that eliminates the code(s). If not, then what should be done is plug in a scanner, take the vehicle for a drive, and at wide open throttle compare the throttle position relative to the MAF sensor reading. So if at 100% open throttle the MAF sensor see’s less than 100% mass air flow, the MAF sensor is the problem.


I think the answer is fairly clear. Since this problem is obviously connected to you going to or coming from work, you should just stop going to work :wink:

Anyway - you have air, fuel, spark, and compression to worry about. The MAF cleaning is about the computer’s reading of airflow. It makes sense for the symptoms and is easy to clean. So I’d certainly follow Tester’s advice.

You said that you changed the plugs but didn’t mention the wires - ? It would be a little odd for the P0300 to come from bad wires - you’d not expect all to be misbehaving at the same time - but they are likely all the same brand and age. Stranger things happen and new wires are not a bad thing at all.

Get a fuel pressure gauge on it and check out your fuel pressure & supply - especially what happens to it when the truck is shut down and also what it does from a cold start. Presumably it runs rough on start up at times? Maybe not. But a fuel pump that has a bad check valve and/or is on its way out is a possibility.

I’d also take a look at the wiring harness for the fuel injectors and give the injectors a listen while the engine is running. If #3 & 7 keep popping up you might try swapping fuel injectors just to see what happens.

If you get reasonably certain that spark and fuel are in order a check of compression is always good before too much tail chasing goes on.

Not going to work is quite an idea. What’s that movie? A Streetcar Named Retire?

Random misfire could also be an iffy crankshaft sensor.

You do not say if this is the 3.7 engine but if it is there is a TSB about this 09-007-06. The fix is installing “revised intake valve locks and intake valves”. The TSB states the condition will set single or multiple cylinder misfire codes and is more common to happen at idle,like just leaving a parking spot.

Checking for TSB’s should be high on the list when diagnosing such a concern.