Replacing the coil back fixed the bad miss at idle but still not running right. All grounds are good, checked them least night. Going to be out of town until Monday and plan on swapping injectors. If they aren't the problem I can save them for the '67 Camaro as they are 34lb ers and it'll need it.

 

So the issue still continues, it's also sputtering for a split second on start up now. Idle is slightly worse than normal but still only chugs once it fully warms up (15 minutes of drive time). Fuel pressure checked out good, replaced fuel filter anyway. New (used) fuel rails, injectors, & FPR and nothing changed. Bought one new coil pack and tried on all cylinders and nothing changed. All plug wires are have less than 20k miles and ohm out good, plugs are brand new coppers. I'm running out of ideas here.

Camshaft sensor, crankshaft sensor, any ideas?

 

I feel your pain man. I'm dealing with essentially the same issue with me truck. Even got a thread on it. Mine is goin to a mechanic shop tomorrow that I know can figure it out cause they're great. But I've done almost everything you have. My truck is missing on #7. A mechanic friend and I are beginning to wonder if the driver in the computer for that injector is going bad. You may wanna try a pcm swap if you have a spare lying around.

 

The odd thing is that it's very inconsistent so I dont think it's a computer issue. I can't even figure what cylinder it is.

I hope they figure out what it is wrong on your rig soon.

 

Can you get a timing light to check your spark with? That would be a good start towards tracking down a dead cylinder.

 

I actually used a timing light a few days ago and all cylinders checked out good. The fuel gauge I have doesn't leave me enough cable to watch it when driving around and being the chugging only happens under load and after it is running for about 15-20 minutes I’m wondering if it’s a failing fuel pump. I have a spare one in my toolbox that I’m going to throw on tonight and see if that does anything. Next step if that doesn’t work I think will be to swap the crank sensor with my buddy’s truck.

 

Is this truck completely stock? Do you not have anylogging software?

 

This is an ’02 5.3L motor that I swapped into a ’67 Bronco. The motor is stock except for the typical ported TB, intake, exhaust, mail order tune. I do not have any data logging software but I do have a code reader that reads live data and haven’t been able to spot anything peculiar.

 

Since it's an '02 it still has a vacuum referenced fuel regulator correct? Have you checked that for a leak or replaced it?

Also, have you removed the fuel rails from the injectors and flushed those out to ensure you don't have "trash" floating around in there affecting different cylinders? While you're at it, check and possibly replace the injector O-rings if they are rotted out/worn.

Can you check fuel trims from the ECU to see which bank is doing the F-UP?

 

It does have a vacuum FPR and it has not been replaced, yet... Fuel lines and injectors have been removed and thoroughly flushed. I actually put in a different set of injectors that I had lying around to make sure too. Rig has a new fuel filter and fuel pump. My friend checked the FP a couple weeks ago and said it looked good but I went ahead and bought a FI pressure tester kit today because it just seems odd. Below is what I found:

Key On - Spikes to 60, immediately drops and holds at 52psi
Idle - 47,48psi steady
Light Rev - 57psi, as motor struggles the needle bounces around about 2-3 psi

Should the needle be bouncing around like that?