so I have been lurking for a wile and i finally need some help

A couple months ago my ranger developed a occasional studder under heavy loads at highway speeds when trying to pass or going up ramps.
however last week it started to miss hard, but intermittently, and sometimes even dieing.
when it is missing the entire driver side bank is dead, its just running on the passenger side 3 cylinders. I have replaced all the usual suspects, plugs, wires, coil pack, cleaned mass air sensor.

I feel like i have all three pieces, fuel, spark, compression...

i can almost literary watch the spark all the way to the plugs.
when its missing i can smell the unburnt fuel out of the tail pipe.
It runs effectively on all cylinders for long periods of time

what am i missing?

 

More info is needed. What DTC's is it kicking up? And the coil pack you replaced, was the replacement new or junkyard? Since you said its an intermittent problem, is it damp or raining when it acts up? When it fails, it the engine good and warm or can it happen anytime?

 

Won't kick up a CEL on OBD1.
ask me how i know that one. lol
But he is right, a bit more is needed, like temp, was it wet in the morning, that stuff. did you check the MAF and IAC also. just to be sure.

 

Mine is doing the same exact thing!!!! I hate it!!!!! I just replaced my plugs and wires.... still misses. I pull off each plug wire individually while it is running and it gets worse so i dont know why at this point. I took my Boggers off for some stock wheels and tires and i don't notice the miss as much under a load but when you rev the motor it is definately there and i have a lack of power. Wet or dry, hot or cold, day or night, left or right, up or down... it is always there. Made me put a for sale sign in my back window and i am not kidding.......

 

i used all new parts, and sadly the weather doesn't seem to affect it.
Its as if a switch is flipped and i suddenly loose half my engine, i had to drive 20 mins home the other night with it running on 3 cyl :(
going to investigate the IAC this afternoon when i get up (3shift) and hopefully i'll luck out

forgot to mention that the check engine light is on when it runs crappy. Flips back off as soon as it stops missing, however there's no port under the dash so kinda confused as to the whole purpose of the light at all.

 

I know with the 4.0 misfiring could relate to a cracked head. Its common with these engines. I'm not saying that is for sure it but its something to look into.

 

I expected that it would trip the CEL when it was acting up. Once that light goes off, the DTC (aka, "the code") will be stored for 50 duty cycles. Pull the DTC and post it before it clears itself. I jettisoned my 94 quite awhile back, but I know there is a port in there, I actually had to use it :( . If it's not under the dash then look under the hood, back around the power brake booster, and on the back side of and attached to the fuse box in that corner. As for the purpose of the light, it indicates that a fault has been detected in the engine management system, and by extracting the DTC(s), a specific area can be focused on to resolve the problem. This greatly simplifies resolving problems, and takes care of a whole lot of random guessing, buying parts and hoping for the better (aka, pay n' spray), frustration, and time.

The reason I asked about the weather and dampness was because, I've tracked weird misfires to electrical components that are impacted by moisture. On this note, I still gotta ask, it there anything you notice or are doing at the time this is happening? Anything different, maybe operationg conditions, no matter what it may be, would be something to make a little mental note of right now. Not that it will be needed, but in a general sense, just be aware of any circumstances for now.

One final suggestion and in the spirit of solving the problem sooner, instead of fiddling with the IAC this afternoon, pull the DTC(s). There are three types KOEO, KOER, and CM. Pull all of them and post.

 

After playing with it today, i realized that i was wrong about the entire driver-side bank missing. originally when i checked it, i checked all the cyl individually by pulling a plug and replacing it. there was no change in the sound or rhythm no mater which driver-side plug-wire i pulled.

however today when i pulled more than one wire off i realised only one cyl was missing, but it would change depending on the order i pulled the plugs off cyl 4 5 or 6.

anyway the KOEO blinked this at me 341 341 111 1111
i realize that 1111 is really 112, or 121, the throttle position sensor, or the crank angle position sensor, but i ran it several times and wasn't able to verify one way or the other.

the KOER blinked 1 412 411 538 536 412 538 535
so now my theory is that my TPS is wonky...

 

Gotta fix KOEO codes before fixing KOER codes, and fix both of these before fixing any CM codes. Within a group, start by always fixing the lowest code # first, which in this case is 341. There shouldn't be any 1111. Check to see if the jumper on the octane adjust jumper is in and not grounding for 341; this is the first code in the sequence assuming that 1111 was a 111). Once this is fixed, clear codes and repeat the test. When doing the KOER test, always remember to press the brake and quickly stuff the gas pedal to the floor for a sec when directed to do so; not doing so will cause bogus codes to appear. The system is checking things like the brake switch, and TPS, to name a few items, at this point.

*Gotta fix codes in the sequences noted above, as the causes for one code can trigger another code, of which that code goes away when the first problem is fixed. Hence, the sequence must be followed.