2001 Supercrew 4.6 engine sputters

Hi guys - I just had the blown engine in my Supercrew changed out with a used engine I bought that was installed in a 2002 Marquis.

The engine sputters at idle and going down the road like it's missing on one cylinder, however all eight plugs are brand new, and there is no check engine light.

The miss goes away going downhill, but on the level and going uphill the sputter comes on for a few seconds, then goes away for a few seconds, then comes back etc.

I have two spare coils, and I could replace two, however again I have no check engine light -

The truck sat for like three months after the engine change while I was paying off the bill for the labor - my other thought would be that the timing on this engine may be off a bit, or possibly I need fuel injector cleaner and a fuel filter change.

This Romeo engine I got from a Marquis had to have quite a bit of parts changed over from my existing engine for it to work in the Supercrew.

Ideas? Any input will be appreciated. Without a check engine light can the local Pep Boys do a diagnostic? Thanks Prof

sounds like injectors to me. You need to hook it up to a scanner and tourqe it up in the driveway. Ie foot one the brake and the gas at the same time. It loads the engine to simulate conditions without having to drive it. You should see the miss in real time, it may not be missing bad enough to through a code. FIRST swap coils and see if the miss follows the coils, it is way to easy to not do it first. Next you can do the same with injectors, they aren't that hard to swap either. If the coils in injectors are bad you cannot fix em. If they are plugged up, fuel injector cleaner isn't going to help either. I have bought a reconditioned set off ebay from "fuelinjectionconnection" user before for around 100 bucks for the whole set of 8. They worked great, so he has good stuff. If you have any intentions of camming it or anything in the future get some higher lb/hr ones while you are at it. The coils are not uncommon on this family of engines either. If you swapped out a blown one do you have the old for parts? If so, you got cheap parts sitting around.

While idling, remove the connector from one fuel injector at a time. The reason I disconnect the fuel injector instead of the COP is because this prevents unburned fuel getting to your cats. If you hear a change in engine RPM/roughness, it is not that cylinder - move on. If you pull one and the engine stays the same, that's your problem cylinder. Replace COP and see if that works. If not, check spark plug, and if that checks out, pull the injector.

Pulling the injectors can be time consuming, atleast if the crash bracket is so inaccessible like in the Marquis. It is an operation that you could do in your garage in an hour or two if you're patient and have basic hand tools. Once you get the intake off and loosen the bolts holding on the fuel rail, they just slide right out. Just remember to use motor oil on the o-rings when re-installing for easy installation without tearing o-rings.

Hi guys - just to close out this item - the check engine light finally came on while driving and it indicated #8 cyliner misfire. R&R coil. Ops good. Thanks on the info. Prof