Im not real familar with the Ford computers and dianosing where the problem is located, I've had 1 other CE light....the fuel system which turned out to be a gas cap seal problem, I can only hope this is as simple as that was.

I had the truck scanned this morning and problematic code is PO174. I've never heard of this problem before, Im just used to the whole engine being lean or rich not just a particular side. I've been building an old Camaro so this is kinda marbles to me.

The truck in question is '98 F150 XLT 5.4L 97550 miles-daily driver.

I've had to switch to full synthetic 10-30 oil because of the oil slipping past the rings-before I was using a quart of oil per week and now I use a quart every 2000 miles/3months. I just got back from California a few days ago and had no problems, it ran like a champ at 85-95mph. Once in awhile the engine runs rough and shakes the truck. I have a hyperschit chip for it and CAI and a cutout with FloM muffler.

 

step one.. do a search for your CEL code on the forums

I believe that references to a vacuum leak in the pcv to throttle body lines.

 

hey i have a 97 5.4 at 97500miles with a similar prob. it runs lean on the left bank (passenger side) i replaced the pcv valve and it fixed much of the problem and i got back a lot of power. its a 3$ part and an easy fix. however, i still have the shake and lean problem. i know that its definetly a vaccum leak and i believe that is your problem also. have the truck running and allow a friend turn it off and listen really close to the engine for a air suction sound. if you hear it, youve got a vaccum leak which most mechanics can easily fix.

 

Okay I found the holeS the entire PCV line was trashed. $44 for 3 complete new lines via the Stealership. I took off my TB and Elbow for cleaning and polishing lots of sludge was present. No worries I've P&P before.