I swapped over the IAC, IAC Body and MAP, i didnt bother with the TPS because the screws are like Locked in, and they look to be bout the same, dont think that would cause a misfire tho..........

cut off the manifold key?

 

So this morning, i changed plugs/wires from #4 to #3, Aaaand #4 is still misfiring, im just puzzled how it could read 125psi and misfire ALL THE TIME


Swapping the plugs/wires, totally eliminates the wire/plug to that cylinder being a possible issue

Lifters are Good, rockers function perfectly, and i read theres no lash adjustments due to hydraulic lifter

Distributor is not a possible issue (Possibly the Cap, but i wouldnt think so)

No P1391 (Cam sensor) code now, just P0304 (Cyl 4 misfire)

Can i take out the fuel rail w/ injectors, point it away from the engine and Watch the injectors spray??? That would 100% establish - Fuel delivery

I sprayed the intake/ehaust gasket and intake area for any signs of vacuum leaks, and not a single change in RPM's

I suppose im gonna do another compression reading today to see if theres any change from 125psi on #4, im still looking for someone with a cylinder leak down tester

AAAANNND just for ****s n giggles, im gonna put the 2.5TB back on juuuust to see what happens, at this point, it could be the most retarded thing EVER

 

I know its a triple post, but im soo damn aggravated with this

it just drove about 15 miles, it started on 3 cylinders, half way to my destination i noticed that it was running on 4, i get a Block from my destination, confirmed it was running on 4, then pulled up to my destination after down shifting, to hear it idle on 3 cylinders

 

Do you have a fuel pressure gauge that you can attach to the test port on the fuel rail? If the injector's not firing, the fuel pressure should spike.

 

no but i could use one at O riellys

Ive been looking up P0304 all morning and some people had bent push rods and some ppl had locked lifters, bad injectors and another was something about a TB....

the thing is, its effect isnt the Same EVERY TIME... Sometimes it may shake much harder, sometimes shakes just lightly, then when it goes away, obviously nothing shakes, but this is Very Very strange

Today it has ran more on 4 cylinders than on 3 cylinders

Im going to swap out the Crank sensor just because i have another one, i dont expect a change in result, but ill give it a shot

I may even try swapping out Rockers/connecting rods on #4 with what i have from the head i pulled (Even if the head isnt a problem, i can still sell it for more than what i paid)

 

Evert rebuild I have done I always kept the same lifter,lifter shafts and rockers I label them so as not to get them confused so # 4 will be back in #4.

 

Thats what i did, but i just pulled another head so i have rods/rockers from the one i just got


Because its been running on 4 cylinders ALOT today, im leaning more towards something on the electrical/ignition side

But being a 2.5 doesnt the main coil that go to the Dizzy throw spark for the distributor, it doesnt throw spark to a specific cylinder, so the coil cant be bad...

 

Well they are cheap at any store around $15 check yours for cracks or worn terminals I have replaced mine 3 times.

 

I have seen where coils do quit producing spark at weird times in weird intervals. Mechanical things aren't intermittent- either they work, or they are broken. Electrical things rarely break- they just quit working, then start working, then quit working, then start working....

 

According to some of the posts i saw for P0304, some guy argued that mechanical issues could be intermittent, How that works IDK


Ignition coil is $29.99

Dizzy cap is $9.00

Rotor is $9.00

Aaand idk if the ECM going bad is a possibility, but i need to solve this ASAP before that truck gets pulled out of their yard, they are VERY hard to find

EDIT: Just did a Fuel pressure test, it was 50psi, but was bouncing between 47/48 to 50psi in idle, then if i pushed the throttle, it would stabilize and stay steady at 50psi