Still having problems with my 2000 5.0 Explorer

[cantornikolaos]

I bought a 5.0 AWD Explorerin the late summer, 2020 to replace the '04 that needed timing chains. I love 302's, but I wish I would have just spent thatmoney fixing the '04 Explorer. Since I got it registered, it has been nothing but trouble, which shouldn't be normal for a 5.0. It has been misfiring and no matter what I do, it wouldn't run right. Compression is good. New plugs, wires, coils, fuel filter, and it still gave me trouble. I got two injectors replaced and cleaned the fuel rail on bank 1, and that seemed to help. It ran pretty good for a month, but I've been getting catalytic converter efficiency below threshold codes. Slowly, its idle deteriorated to a loping, hard idle and guess what? Cylinder 3 is misfiring again. Possible caused by cat? When I start it cold, it runs good. When I'm driving, it runs good, but it feels like it needs more power. When I'm idling at operating temperature, it stumbles. If I put it in neutral, it idles smoother, but still a little bit of misfiring.

I'm inclined to think the misfiring because of the catalytic converters. I am broke and desperate right now, so I'm afraid to pull the trigger on new cats if I don't absolutely know that will fix things. This truck has other issues and willbe a project for a long time, or it will be a domor for someone else's project, or a winter ride for someone. I'm thinking about moving the secondary cats to the upstream position if they are not damaged and removing thedamaged ones. There are secondary cats, but no O2 sensor behind them.

 

[C420sailor]

Don’t mess with the cats yet. That could just be a bad downstream oxygen sensor.

Basics. Fuel pressure? Test for vacuum leaks. Clean your MAF sensor. What’s your ECT reading at start and once warm?

 

[Mbrooks420]

I’d only replace injectors in complete sets. What plugs and wires did you use?