jeepin_junkie

The problem started a few days ago and my truck sounded like it was running on 3 cylinders and it was throwing a knock sensor code. I replaced the knock sensor which cured the CEL but still running on 3 cylinders.

I pulled each plug wire one at a time with the engine running and listened for a change in idle and I found out cylinder 3 was didn't make a difference when I pulled the wire. I was getting spark to the plug and the plug looked good so I listened to the injectors and bingo, injector #3 was the only one not ticking.

After inspecting the injector wires and everything looked ok I decided to buy a set of injectors from injectordyne on ebay. After replacing the injectors, I still had a slight miss at idle that went away when revved up and the truck was running ultra rich and backfiring when letting off the gas at cruising speeds.

I thought I probably had an intake leak between upper & lower plenum but spraying carb cleaner while running didn't change the idle at all. I ended up taking it apart again and replacing the gasket again but this didn't change anything.

I have tested the AFM and the TPS and they seem to be within spec.

I really need this truck to be running, any advice is much appreciated as I have searched and searched and searched the forums but haven't found the solution yet!

Flash319

Looks like you have checked most things. The only other thing is the cold start injector. Maybe it is staying on or leaking?

Oh ya just for your info. 22re engines all injectors fire at the same time. Also I have found that pulling plug wires on them does not tell you much as there is not much change when idling on 3 cylinders. You don't see a difference until you are down to 2 cylinders.

jeepin_junkie

I unbolted the cold start injector from the intake and left the gas line hooked up. Unplugged electrical to it and pressurized the fuel system by jumping the B+ and FP terminals, no leak at cold start injector...

I put the cold start injector back in and left electrical unplugged and ran the truck and it is still running rich (rough idle, i can smell fuel coming out of the exhaust)

jeepin_junkie

The truck runs perfect when I start it up and it's in open loop (or does it start in closed loop?) but once it goes to the other loop thats when it starts missing and everything.

The miss is not only at idle but you can notice it around 2200-2500 rpm and maybe other ranges but most noticeable in that range and at idle...