Truck started shaking and running bad last weeks. Check engine light came on, I checked codes P0308 and P0171 came up. I have changed all the plugs and checked the injectors and also the coil plugs. all seem to be fine, Truck will some times start fine and run fine. then go to a store and restart it and it would start shaking again. then come home and go out again and it would start fine again. once it starts fine it stays that way. When it starts and it's shaking it stays that way. I thought maybe the gas seeing it happened the day after I filled the tank. But got a new tank of gas yesterday and it's still doing it.

 

Replace # 8 coil unless you moved it to another cylinder and it shows up faulty in that cylinder.
There is no 'checking' them for intermittant failure.
Recheck for codes since they may have changed.
The 171 code likely was generated due to the cylinder missfires being detected as a rich condition (unburnt gas).
Good luck.

 

I did change the number 8 coil. still no luck, thanks, Number #8 is on the drivers side right?

 

If the code has not returned for cylinder 8, you fixed it.
There are other issues.
Sometimes tough when more than one problem exists at the same time.
Just have to sort them out one at a time.

 

Thanks, I reset the computer and the check engine light does not come back on. but it still starts bad and shakes. I had someone change the spark plugs and they said there was oil on the spark plugs. Could it be the Fuel Filter, I have never changed that since owning the truck about 3 or 4 years now.

 

po171 engine running lean; check for vac leaks, maf dirty, dpfe sensor, fuel restriction/ pump weak.

 

common place to get po171 code is air leak thru burn vacuum hoses. Check the two 1/4 inch hoses above the driver side valve cover, about 8 inches long each.

 

Thanks, I'm starting to think the guy who checked my #8 coil did not really check it. Anyway he could have pulled the #8 coil in less then 10 mins? I have seen vids and it does not look that easy.

 

He may have checked it, but you can get a coil that tests good that is still bad. Once a coil warms up, it can misbehave. As for the lean code, it usually indicates a vacuum leak, but it is not registering on the same bank as the affected cylinder, so you might have two unrelated problems going on.

 

Started the truck this morning and it took like 3 turns to crank over and I was checking over the hoses and the engine almost cut out. seems to rev up and down, wondering if this is a fuel filter or fuel pump problem.

 

Pulled the #8 coil and changed it with the #4 coil and noticed the #4 smelled like gas on it.

 

#4 is the back on passenger side and #8 is the back on drivers side right ? Why did you pull #4, thats one of the hard ones to get to ? Dieing when you wiggle vacuum lines is probably a good location for a vacuum leak.

 

I changed #4 because that's where the person I had install the new coil put it. The vacuum line on the top of the engine looks brittle.

 

I pulled the injector plugs while the truck was running and 4 of them 2 on each side had no change. could this be the problem?

 

The surging idle along with your 0171 code is a common symptom of a bad pcv valve ( the plastic elbow thing with a ball in it in the middle of your passenger valve cover) or a torn hose that connects to it ,that leads to the back of the throttle body