I have a 1997 Ford F150 XL Extended Cab with a 4.2 Liter engine. The engine itself is actually new. Well, remanufactured new. The heads and block are remanufactured, but all internal parts from top to bottom are new. Along with new water pump, new plugs and new wires at installation. Ignition coil has been replaced as well. Engine came with a new oil pump, oil pan, valve covers, etc. Engine has less than 1,000 miles on it. I've had it back for a couple of months now. But it's getting this random misfire. And I know it's a misfire, because the Check Engine light starts flashing. I know many of you are going to ask that famous question, "have you read the code yet?". No I have not. I do not have a scan tool of my own. And when the issue pops up, I am never near an Autozone or Advanced where I could pull in and have them run it. And I am hesitant to drive it when it happens, because honestly, it feels like it's running on 3 or 4 cylinders out of 6. Plus, I don't have the heart to run the new engine like that. But here is the strange part. I can pull over, unplug the battery for about 5 mins, and it clears right up! Misfire goes away and it runs like a new engine again! Don't get me wrong, the engine runs fantastic. It's just this weird, random misfire I am getting. Now while disconnecting the battery does clear it, it does come back after 50-100 miles. And the same solution solves it, temporarily. I am intent on buying a scanner. And the next time it happens, just pull over and read the code or codes myself, then come home and google them. Right now, I am hoping maybe someone out their has had somewhat of a similiar experience. And might be able to help steer me in a starting direction. Maybe share your experience and what you did to resolve it? Thanks to anyone who replies with any suggestions.

 

Code readers are really cheap. May be time to order one.

 

What about the fuel injectors?

 

Fuel injectors are off the old engine that was replaced. Can they cause a random misfire? I bought an OBD scan tool. Still waiting for the issue too arise again so that I can read the codes.

 

You might want to throw some Techron in the gas to clean the injectors.

Did you use Motorcraft plugs, wires, and coil? Have you verified the wires are routed correctly and in the correct coil terminals?

 

I honestly dont recall the brand of the coil. Its kind of complicated. The wires, plugs an coil were replaced on the old engine literally a month before it quit and were carried over to the new engine. Wires are Motorcraft I am pretty sure. And the plugs I used at the time were motorcraft platinum. However due to the state of failure of the old engine, the plugs were replaced again with the new engine. But I wasnt the one that did it. I would have to pull a plug an see what brand they are.

 

The cam and lifters are new also?
chronic misfires usually for me always seem to lead back to a bad lifter and worn cam lobe. Possibly a sticking valve as well.

 

Yes, all that's new. Lifters, rods, cam, crank. valves. I scanned the check engine light when it came back. All I got was a P0455 code. Evaporative Emission. In my situation it seems to be a pretty common code these Ford trucks around this year model like to throw. Check engine light period is sensitive. I believe it's something to do with the charcoal filter, or whatever they call it in the back. Doesn't explain the sporadic misfire I was getting. I also dumped some fuel injector cleaner in the gas tank with some fresh fuel. Just trying to run and drive it right now. Get the fuel injector cleaner through it. Haven't gotten the misfire back. It's been several days now. It's kind of weird.

 

https://www.obd-codes.com/p0455