First off, I'm a Old School mechanic 62 yrs young. Give me a carb motor no problems. Built & raced my own for many years. But EFI, I'm lost.

Installed Thorley Tri-Y mid headers, True Duals, cutouts, X-pipe, dual FM 50HD mufflers SI/SO, cats deleted, downstream 02 sensors hung, and 3" pipe off the headers to the back of the r/rear tire.

Here's the codes I get w/ superchips:

P0300- Multiple cyl Misfire
(forgot#) 1/1 sensor rich
(forgot#) 1/2 sensor lean

I have cleared the PCM w/SC
Cleared PCM by disconnecting pos batt post and grounding it on neg post. (Hard reset? Found tip on HTC)
Removed TB & PCV and cleaned them off the truck.
Checked upsteam 02 wires & connections. All OK.
Checked all injector & coil pack connections. Tight & Locked.

I know 1/1 & 1/2 sensors are upstream.
No exhaust leaks.
Doesn't throw downstream 02 codes.

Truck will idle for 3 hours & not have a code.
Take it on the freeway, fine for about 8 miles, then gets multiple cyl misfire code and if you floor it, the trk has no throttle responce 'til the peddle is at the floor then it drops 2 gears @ 70, stumbles more for about 2 seconds, then wham!!, all 8 cyls start firing and take off like a rocket. Soon as I let off, starts misfiring again.

I am at a loss because I searched 4 forums, asked other gearheads, & no way that I've found to fix the misfire.

I'm about to pull the rest of my balding hair out because of this.

 

First of all, I can't fathom why you are not getting a lean code for bank 2, sensor 2 like you are on bank 1, if they are just hung? Obviously measuring outside air is your lean state on bank 1, sensor 2.

A multiple, random misfire with no cylinder specified is almost always caused by running lean or a vaccum leak. Is your EGR stuck open possibly? If not, it's time to get an A/F ratio reading on your truck.

I think the sputtering is your front O2 error though. I'd drill and weld a couple of bungs for the rear O2's and run non-foulers, hell at $5 a piece, there is no reason not too. This could possibly also clear the front O2 (I've seen it happen).
If not, you've got to find out where the rich code is coming from. Which of course, does not coincide with your misfire CEL, which is indicative of a lean state.
Again, only by checking your actual A/F ratio would you know what is really going on, allowing you to narrow down the possible causes of your issues...

 

Thanks Hammer.

Going to exhaust shop after lunch.

 

Keep us posted...

Also, if you need it, I've got a DIY, with pics, in the FAQ section on doing the NON-FOULERS...

https://dodgeforum.com/forum/3rd-gen...ving-cats.html

 

Followed some suggestions and it's FIXED. Drove about 20 miles & no codes.

Welded bungs in L/ collector & for downstream 02s with non-foulers.

I unwrapped my #1 sensor wires out of the loom and over the tranny in order to reach the drivers side. Pain in the butt to do as they were entwined with the other 2 sensor wires. Long process but it worked.

Thanks again Hammer!!

 

No problem, man.

That's what we are all here for...