I could really use some insight (once again) from folks that know a WHOLE LOT MORE than I do.
I have a 84 F150, I6. I re-sealed after having block/heads cleaned (engine put together by a mechanic by trade, even if he does work at a chevy dealership). I swapped the TFI for DSII (EVERYTHING is new and good quality except wire harness). Carb is 2100 I rebuilt and did my best to set to specks from sheet (but still my first carb rebuild). I also bolted on EFI ex. man. and Offy DP (doubt them have anything to do with problem, but mentioning all). The only thing I did to heads after cleaning was new valve seals.

I have a miss in #1 or #2 cyl.(confirmed and fiddled with by neighbor who is a mechanic) and can't figure where the problem is. It idles SOOO rough I have to feather gas to keep running, but once the RPM's are up a little bit, it smooths right out.

I HAVE NO CLUE WHAT IT MIGHT BE!!!

Engine was sitting for 5yrs in dad's shop/building after cleaning and lower end put together before I was able to finish putting together.

I'm going to change the "fancy" iridium plugs to basics here shortly to see if any change.

If it would help, my cell is 502-408-1528

 

I would check for a leak where the intake seals to the head/gasket. Those are classic symptoms of a vacuum leak.

Check the torque on all the mounting bolts then adjust the idle high enough the truck will keep running and spray carb cleaner all around where the #1 & 2 intake runner mates to the head/gasket to isolate the leak.

 

"...classic symptoms of a vacuum leak." X2.

"Carb is 2100"..." Offy DP" How did you mount a 2v carb on a 4v manifold that is only designed for 4v carbs?

 

I would determine for sure whether its mechanical or electrical by doing a compression test and putting a vacuum gauge on it. Two modest-cost investments good for a lifetime.

 

X2

Hang in there.

 

Good advise thus far given..........

Don't discount a poor block ground(s) too.
Inspect your negative battery cable that goes to the starter bolt.
Remove all the block negative grounds and wirebrush them including the negative battery post clamp and the negative battery post itself.
Cylinders 1 & 2 are the longest spark wires (most resistive) and they'll show as a "miss" before wires 3 thru 6 will.

Just my .02 cents.


Bob

 

You may want to check to see that the PC valve is sized correctly?..or that the brake booster may have a vacuum leak?