Toolcrazy808

Aloha All....

It has been a long year with not having my truck. I took the truck to a mechanic and let me say I trust his ability and knowledge. The reason I took the truck to him was because the truck had a miss that I couldn't get rid of, changed plugs and coil packs several different times. While he had the truck the #6 piston decided to not want to be in the engine block anymore. It took me some time but I was able to get a new engine it was a slightly modified long block from Pomar engines in New Jersey. After the engine was installed the truck still had the miss. We had changed out the coil packs and plugs a couple different times we also have changed out the injectors and still has the miss. we have learned the miss is on one side of the engine the right side bank and is random between 1-4 also happens when the engine is coming off of a rev, I was able to get a different ECU from the same type of truck and we still have the same miss. I just ordered a brake out box so we can try and pin point where the miss is coming from, Fuel side or Ignition side.

I am writing this hoping someone here has seen something like this and could steer us in a direction. It had been a year since I have driven my truck and I really miss it.

Mahalo for any help.

mbb

What kind of plugs and coils?

Codes?
Fuel trims?

Toolcrazy808

At this time the plugs are stock ones Motorcraft I have had NGKs in prior to taking it in I believe the coils are Motorcraft as well I have had several dikind in it to try and eliminate the miss.

No codes it never threw a code for a miss. As far as fuel trim it’s what ever stock is I never changed them.

Aragorn

I would suggest getting something like a BAFX scanner for either or and a copy of Torque Pro or Forscan if you use a PC. Get the actual fuel trims as it is running and it will tell you where the misfire is. If you are misfiring you should also get a blinking Service Engine now light and a code. It'd throw a P030X (where X is the cylinder.)

white89gt

If it's not throwing a code, I am curious how you know it's a random misfire between 1-4?

fordguy2100

Butt dyno

mbb

I dont trust your mechanics ability or knowledge.

Fuel trims will show you if you are lean or rich,

Theres no readon to assume miss on new motor is same as old. It might be. But your starting from scratch. Too much was done.

Manifold leak or vac leak is a suspect imo, if you replaced plugs/coils.

Little experimental changing parts needed by a real mechanic.

white89gt

Yeah.... after a year if you can't figure it out... I'd find a new mechanic.

JCR 56

Or an actual mechanic.

white89gt

Yeah... the term "mechanic" was used kind of loosely there, LOL.