Engine/Transmission (1994 - 1998) Intermittent Miss, comes & goes

[ZBrown]

Basics - - 94, 160 pump, 0 plate, 4kgsk, stock injectors + DV's, 190k



This started awhile ago but it is getting more and more frequent. From 1. 7k+ rpms i get a complete miss from one cylinder that i can hear easily out the exhaust and feel, not a slight miss, a cold cylinder miss... .



It will do it sometimes just cruising but usually does it 90% of the time during a WOT burst



It is like someone flips a switch when it happens too, like on and off, it runs flawlessly when it is not missing but then it will snap into a miss for a few seconds and then a few seconds later come out of it...



I was thinking it was just air but i have bled and rebled, so that is not it



Fuel press is good



sidenote... . when i first installed the 4kgsk it would breakup above 3k in neutral with a #5 plate... ..... then i switched to a 0 plate and it runs clean to3. 5k+ with no breakup at all now





I am hoping it is just a sick OEM injector causing this, as i am saving for a set of DDP's, and not the pump?



any ideas?



thanks zac

 

[Fordiesel69]

Does the miss last long enough that you can crack an injector line to find out? If so swap the injector with any other cylinder and it if follows, you know it is an injector.

 

[ZBrown]

^^^^



yes the miss lasts long enough sometimes, but the problem is the engine has to be under atleast some load to do it..... it wont do it in neutral



so i would have to have the pickup moving and then crack the line

 

[Fordiesel69]

^^^^



yes the miss lasts long enough sometimes, but the problem is the engine has to be under atleast some load to do it..... it wont do it in neutral



so i would have to have the pickup moving and then crack the line

Have an assistant put in it reverse and accelerate slightly while you are cracking them. Just make sure you have no loose clothing that can get stuck in the fan. Don't ask me how I know. Another way is to get an expensive laser thermometer and point to each exhaust port, that will get you to 1-2 cylinders. If it is a cheap 50-80 dollar one forget it as the contact area it reads is too big. The little red laser is not actually what is doing the reading.

 

[Buck88]

Did you check timing at all? Just a thought.

 

[ZBrown]

Did you check timing at all? Just a thought.

Yeah timming was done at a trustworth shop a couple of months ago, from 12. 5 to 16. 5... ... must be right because it runs much stronger at the higher rev's