I have a 2000 F150 Flareside XLT with the 5.5 Triton motor. 147K miles.

Been having a lot of problems with the truck running like crap for quite a while now. Had a misfire in cyl 1, had spark so I replaced the injector and all was good for a short time. Problem came back so I replaced the coil and the problem came back. Checked the compression and all was well, replaced the spark plug and again temporarily fixed but problem came back. Recently had the truck overheat on me, had to add 2 gallons of water to make it home, but there is no noticeable external leak. I swapped the coils for cyl 1 and 2 and cleared the codes to see if the new coil was bad. CEL came on again and pulled a P0133 code today for the O2 sensor, but don't think this would cause the stumble and rough ride I have been experiencing. One mechanic friend thinks I have a head gasket leak in cyl 1, another doesn't think that is the problem. Running out of patience and ideas. Hoping someone on here may be able to help. I'd appreciate any help.

 

Do a compression test, then that should give us an answer we need.

 

I did a compression test last week. It was ~140# if I remember correctly.

 

Oops, missed that.

 

Your friend is exactly right " head gasket". I had all those same exact problems in my 97. I kept trying little fixes like you. The last was a vac hose. That worked for 6 months while I was taking great care of my truck. Soon as I slacked off from watching oil and water levels daily and drove 150 miles straight to the woods and then back in 15 degree temps, I bent the crank rod in cylinder one. It was a bad head gasket creased and folded over from the factory. Turns out ford had a recall up to 90,000 miles on two out of three plants. Mine was the third plant of course and 94,000 miles. Rebuilt the motor and it lasted longer than the truck. PULL THAT DRIVER SIDE HEAD. Look at your oil cap, I bet it has a milky film once in a while but your oil still looks good, FOR NOW.

 

Before pulling a head, do a hydrocarbon test on the coolant. You need to do proper comprehensive diagnostics before ripping into the engine.

 

Thanks guys. I do get a milky film on the oil cap. Never thought much of it until now.

Where would I send a coolant sample for the hydrocarbon test?

 

The milky film on the oil cap is NORMAL. glc laid out the correct test. Do that. It does sound like a head gasket. The leak would be into the combustion chamber. Pay no attention to the oil cap. Normal condensation. I would snif the exhaust smell like antifreeze? headgasket.

 

Parts stores have the kits for testing the coolant yourself.

 

Why are you not giving importance to the 133 code.
It's telling you something.
Forward sensor bank one is having a hard time working from contamination and cooling the sensor to low in temp to work correctly. They need to be at 600 degrees or above.
It's coolant in the exhaust from the cylinders in that bank causing it.
The system is telling you these hints.
Do verify with the coolant test.
Good luck.

 

I forgot to mention the fact that during the last 9 months before my rod bent because of a bad head gasket installed from factory robot. My truck did leak a little too much water out the tailpipe for comfort. The milky oil cap got worse and was more than I wanted to see each time. Also I tended to drive it like a grandma but once in a while on the freeway I would floor it, only to see a good puff or two of black smoke that got worse instead of better each time. Rebuilt the motor and kept the same exhaust. It never happened again, no codes, no problems. Fyi a 1994 crown vic uses the same o2 sensers as my 97 but only has two. As for the head gasket, my mechanic showed me the problem and told me what my truck was doing to me after the fact. He had no information from me but knew all about my engine. I showed up out of the blue to check on him and at the right time to see the problems. I'm just saying save yourself some money and trouble and listen to your mechanic.
Same coded problems=Same coded problems. Use your mechanic friend to help you over a long weekend and take monday off for needed parts and putting it back together. Order and recieve factory fomoco head gasket in advance before you decide to do the job. Get a good manual and you can find reference videos on youtube. I learned the hard way by not listening to the guy that said head gasket and pull the head before it blows. Missing water goes one of two places, in the oil or out the tailpipe or both. My water would be good one day and the next then dissappear at random. Once the rod bent the oil took the water and looked like milk. Changed the oil twice as a last ditch effort to no avail.
Bottom line is not that I'm saying pull the head this weekend.
You do your own homework. I'm just giving you my information and betting you have the same problem I had.

 

I appreciate you sharing your experience. I spoke with a friend who is a Ford certified tech and he is going to look at my truck next week. He has a plan for diagnosing and fixing the issue so I will leave it in his hands. Thanks for all the help guys!