94' sounding very bad at start, still not so great after

[DeliciousKeki]

I dont plan on using this 4.0 for too much longer but this started today and the power loss is huge, i have to nearly floor it just to get up to 40mph or so. Any ideas? For your convience I uploaded a quick video so you can hear exactly what it sounds like.

https://youtu.be/WvzgNMGXs88

 

[MrShorty]

My first impression is a constant misfire of some kind. I might try a cylinder balance test to see if you can isolate the misfire to one or two cylinders.

 

[natenkiki2004]

Sounds like dead cylinders. Gotta figure out if it's spark or fuel. Pretty easy to test the coil pack & wires if you have a multimeter. 1 bad wire will kill 2 cylinders.

 

[DeliciousKeki]

I did a quick cylinder test, RPMs lowered on all cylinders, about the same drop from all. Spark plugs look normal. (Autolite plats)

 

[2stroke]

That's not a dead cylinder, and even if it was, it would be obvious by looking at the spark plugs. You do realize you have a MASSIVE exhaust leak, right? That's certainly not helping. I'm not saying its the problem, but the last time I had my truck idle like that, I forgot to hook the PCV line to the plenum. I would look for big vacuum leaks. Check the vacuum tree, then spray around the engine bay with carb cleaner. After that, I would check fuel pressure. I assume you have new spark plugs and wires, as that's always the first thing to do. I doubt its a coil, but I've been wrong a lot of times before.

 

[FR-425]

An exhaust leak is a huge problem with O2 sensors down stream.

 

[Bmoresports]

check and clean your MAF sensor, also EGR valve and maybe after that if its still not working check fuel injectors.. First thing id say would be the MAF though, probably needs to be cleaned, takes 45 mins max, and most that time is letting it dry..