check engine light on and flashing p303 and p316

[okxlt2003]

I'v posted this problem before and it continues to be a mystery to most how to repair it. Codes p303 and p316. 303 misfire #3 code 316 misfire first 1000 RPM's. 4.6 flex fuel vin code K. 172,000 mile on it. Lack of power, rough idle, it would shudder at between 35 and 45 mph. Ran fine at highway speed. But sucked gas like crazy.

What I've done. Replace o2 sensors, (all 4) replaced coil pack,wires and plugs. Replaced the upper intake pelhum gaskets. Replaced the crank position sensor and changed the fuel filter. Cleaned the MAF sensor and the thottlle position sensor. None of these helped. Granted, none of it hurt it either since it was all over due scheduled maintenance.

I talked with a repair shop here in town. The man here said for me to check the compression to make sure it wasn't a head (valves) or ring problem with low compression. Compression was good. 140-145 on all cylinders. He said that if the compression was good it left 2 things to go for. Fuel injectors or engine computer. I just replaced the injectors,(all six) it is definitly better. Got them thru ROCK auto for 147.00 for the set. took them out of the box and they matched my old ones. So I'll drive it and cycle the cumputer to clear the codes and see what happens. I'll keep you all posted. Hope this helps someone.

 

[matt0248]

I'v posted this problem before and it continues to be a mystery to most how to repair it. Codes p303 and p316. 303 misfire #3 code 316 misfire first 1000 RPM's. 4.6 flex fuel vin code K. 172,000 mile on it. Lack of power, rough idle, it would shudder at between 35 and 45 mph. Ran fine at highway speed. But sucked gas like crazy.

What I've done. Replace o2 sensors, (all 4) replaced coil pack,wires and plugs. Replaced the upper intake pelhum gaskets. Replaced the crank position sensor and changed the fuel filter. Cleaned the MAF sensor and the thottlle position sensor. None of these helped. Granted, none of it hurt it either since it was all over due scheduled maintenance.

I talked with a repair shop here in town. The man here said for me to check the compression to make sure it wasn't a head (valves) or ring problem with low compression. Compression was good. 140-145 on all cylinders. He said that if the compression was good it left 2 things to go for. Fuel injectors or engine computer. I just replaced the injectors,(all six) it is definitly better. Got them thru ROCK auto for 147.00 for the set. took them out of the box and they matched my old ones. So I'll drive it and cycle the cumputer to clear the codes and see what happens. I'll keep you all posted. Hope this helps someone.

FYI Vin k is a 4.0 V6. Is this a two piece intake manifold? If so you may need to replace the lower gaskets as well.

 

[okxlt2003]

Ya your right, my error 4.0 not 4.6. I did a eather spray test before and after changing the upper gasket. Rev'ed up before and didn't after. so would be safe to say the lower is probably good.

 

[Argentimage]

I've got the same thing going...was this injectors that fixed your problem?

OR and AZ suggest changing the spark ctrl module but its not getting hot.

Starts fine cold, but once run down the road 5 miles or more, and shut off, this will occur every time.

Plugs, wires, fuel filter are influencing factors that were changed ahead of this issue appearing.