I have a 1999 f250 sd 166000 mi & it has a code po266 cylinder#2 contribution / balance fault. !!!! does this code mean the injector needs to be replaced;; i had someone with a scaner check it & he said he has changed the valve cover gasket & that fixed the miss;can anyone help!!!!!!!!!!!!!! thank you for any help.does anyone know the mieage for the injectors for replaceing them!!!!!!!!

 

Welcom to FTE, you will find the answer to your problem here, and we should be able to save you money if you can turn a few wrenches.

To better diagnose the problem can you post how the truck is currently running, if it has a miss did it happen immediately in all RPM ranges and idle or does it only happen when accelerating or cold.

there are several different scenarios from dirty and burnt UVC (under valve cover) pins, UVC wiring harneses, injectors (does not always mean they need replaced) as much info that you can provide would be helpful

 

Is the engine running bad? maybe after fixing the valve cover gasket, the connector is good now (which fixed your miss) and the code was never reset ?

 

I frist notice the miss at idle; then at take off;;its realy bad at idle;;i ohm out the #2 wires from the injector to the top of valve cover gasket & on the ground i had 3 terminals showing continuity; so i removed the wiring harness & ohm out the harness & it checked ok then with only 1 ground then i plug it to the gasket & it checked ok ; i bought a new harness & put it in & checked it & it checked ok. i started & it acted like it was ok till i throttle it up & back to idle & then it started with the miss again;;;could it be in the gasket!!thanks for the help;; i work for a cat dealer on heavy equitment;; 1st time power stroke

 

after new gasket;new wiring harness;still has miss;;the service engine light doenst come on;;on a snap on scaner it shows the code ;; u think i need to try a injector!! thanks for your help.

 

did you do a buzz test and a cylinder contribution test? Also did you check the pin on the exterior plug for the main engine harness to see if the plug is burnt or corroded?

 

i did do a buss test; & all 8 clicked; i all so looked at the pins on top of gasket; i didnt see any that looked burnt; iam going to swap holes & see if the miss goes to #4. thanks for your help;; it seems like when i start it ;cold that it doesnt miss , untill it warms up. it never turns the service engine light on. it must be mechanical !!!!

 

problem solved;;the injector was bad i replaced it back on the road;;thanks for the help

 

Good going caterpillar....!!