97 f150 4.6l 180,000miles
Well getting codes p0307(cyl 7 misfire) as well as p1151 indicating drivers side O2 is lean..Pulled number 7 plug was whitish indicating a lean condition. The truck only seems to misfire at around 1500rpm underload(i.e going up a hill or something) Replaced plug, checked wires..What should I replace next? o2 sensor? injector? I would guess if ignition side was bad and injector was firing properly the plug would be wet..But wasn't as previously stated the plug had whitish residue on it.Any advice would really be appreciated I am think I am gonna go ahead and find another injector and order o2 sensors.If anyone can shed some light on this for me I'd greatly appreciate it..Its my 1st Ford so stuff is a bit new to me on this truck.Just learning the quirks of these engines.thanks again.
Jon

 

I would suggest checking the o2 sensors, especially since this truck has 180k on the clock. I replaced all of my o2 sensors on my Dakota this past year and it has been running the best it has ever been. However, it doesn't hurt unless you changed them out only a few months ago or less than 20k miles.

From what I've experienced, even with the best o2 sensors out there, they only are intended to last between 80k to 120k miles... depending on the quality of the gas and how hard you drive.

It isn't hard to change them... it is just like changing your plugs on your truck...

 

I really have no idea what maintenance has been done..I work at a Ford dealership and the truck came in on trade 97 f150 lariat supercab 4x4 longbox..Came in with 180k seems to be fine cept misfire and o2 code..I can't complain the truck is pretty clean and I only paid $1000..So I knew I'd have to put a little cash into it.But due to holidays money is tight and I'd like to only replace(for now) what will fix the problem. I dont like the idea of riding around lean with 180k on the ticker..

 

Check all the vacuum lines including the PCV elbow.

 

Well did some diagnosing finally had time and pulled the truck into one of the service bays at work..Def needs plug wires which could explain misfire, I could see them arcing on the engine and upon touch I get small shock. ..And something else I notice would driver side leaking exhaust manifold(donut style 2bolt which bolts manifold to y pipe) Cause the 1151 code? Also noticed I got slow response code(can't remember the number) for that sensor as well? So asking advice gonna replace wires hope the fixes misfire can only be an improvement if it dosnt fix misfire.Let me know what you think.thanks in advance for your help
Jon