I'm new and really enjoy this forum, Thanks to all who keep this up and running.

4WD '87 Bronco II, 2.9 V6,
I am searching for the elusive power miss in my 2.9 V6. When checking the fuel pressure I noticed I could feel the regulator housing pulse and when holding the gauge in my hand I just feel the pluses. The gauge needle stays dead steady (it might have a snubber in it). Is this normal???

Power Miss symtoms:
1. Starts great
2. idles pretty good a little miss maybe
3. running engine cold starts missing a little between 1100 and 1500 RPM (like a carburator car that is not quit getting enough gas to the carburator) as I'm shifting through the gears.
4. Running engine hot missing starts 1500 to 2000 RPM as I'm shifting through the gears.
5. MPG has dropped 2 mpg on last tank.

Specifics on testing to date for the power miss:
1. Check EEC all pass no error codes
2. Change fuel filter
3. Check fuel pressure 40psi (Key on engine off) ,32psi (Key on engine running), holds 32 psi if I throttle engine in neutral and holds 40 psi for more than 10 minutes after key is off (I got tired of looking after that).
4. Lightning test - Wait till dark and look for sparks around the dist., plugs and wires. Dist cap, rotor, wires and plugs about 1 year old. No lightning.
5. Bottle of Cheveron Thechron injector cleaner. (I had to try)
6. Vacuum gauge on intake - dead solid 21 InHg at idle and stays solid as I throttle up. ( I don't think it valves)

Plan to check: (As soon as it quits raining)
1. Timing
2. Figure out a way to run fuel pressure gauge in cab to see pressure while driving.
2. Set the engine to 1500 RPM and start pulling plug wires to see if one doesn't change the running.
3. Pull plugs and look for a real white plug (no fuel) of a real gunky plug (no spark)
4 Look for VOO DOO DOLLS in truck!!!!
5. Check voltage at pumps, book says should be within half a volt of battery voltage.

Can any body think of anything else?

Thanks
87 b2

 

Sounds like you pretty much got it covered. I would suspect a fouled or incorrectly gapped spark plug. As for watching the fuel pressure while driving, you could duct tape the guage to the windshield. Just don't pinch the tube in the hood.

 

most plugs are already pre gapped between 42and 44 is fine on 2.9Li would check your timing that's my problem now

 

Here's the update
Checked timing it was dead on.
Put on my two pairs of rubber gloves and started pulling spark plug wires, I hate getting zapped.
First wire I grabbed to pull the wire made the engine run better (I was just holding on to it I had not pulled it). Pulled the wire and no change. Put the wire back on no change. Wiggled wire made the engine run better. Traced the wire down to the exhaust manifold and lo and behold looked like the 4th of
July. Sparks were flying from the wire to the manifold. Tied the wire up away from the manifold. Every thing started running right.

I got lazy when I changed the valve cover gasket and didn't tie the wire up properly last year it took that long to rub through.

Thanks to all that answered
Happy but embarrassed
87 b2

 

That little stuff will get you every time!