Hi everybody, I have some issues that hopefully somebody can help me with. I have a 99 F150 Sport, 5.4 engine. Between 1500 and 2000 rpm the engine (for lack of a better term) bucks. I"ve watched the tach, and when it does this, the tach drops like the engine actually shuts off. I was told about a year ago that it was probably the coil packs, which were replaced. This didn't solve the problem. I picked up a code reader, and it threw a P0320 code. I was told at this time that the Crank Position Sensor needed to be replaced. As of yesterday that was replaced. Now, about three weeks ago it blew the #6 spark plug out of the head, which was repaired at the dealership. Replaced the sensor, erased the codes, and took it for a test drive. It ran like a new truck at that time no problems (no bucking), and I was a happy camper. Went to the store, and it started again. I rechecked the codes, and the same ones came back up.

P0320
P0340
P0171
P0174
P1309

These were all the codes both pre and post sensor replacement. Would the PCM still be storing the codes even after deleting them? How many of these would have been the result of the #6 spark plug blowout? Are there more issues at hand, and where should I start?

Thank you in advance for any help or insight.

 

So I went back to it today, once it was light again, and found four rubber elbows/hoses that went to the pcv valve and right above the bank 1 valve cover that were collapsing due to age. I went to the local parts store and replaced all of them and it eliminated all but the P0320 and the P0340 codes. I deleted them again, and drove home. The truck is still doing the bucking between 1500 and 2000 rpm. Checked the codes again, and it showed the same two codes, but pending this time.

What does it mean when the codes are pending?

Should I replace the cam position sensors to try and eliminate the remaining codes?

I also saw online while trying to figure out issues, and saw that sometimes there are wires that lay against the ac compressor lines and end up fraying. I looked and saw nothing there. So now I'm back to where I was when this all started.

Any help is very appreciated, and welcomed.