Bronco bucking

[Sarge24]

My problem is the truck runs good and strong ( it is a 1986 Bronco 5.0 ) unless you try to rev. up the engine to top speed or if you are driving and it get's anywhere between 1800 and 2000 rpm it begins to buck and jump so hard that I think it is going to mess up something else. It will not run at a faster speed because of this, I'm skeered to pull out in front of anyone.
I took it to the shop and they put the OBD 1 on it and it said that the ing. mod. was bad so I replaced it, still the same thing and now they have even replaced the dist. and it is still doing the same thing....HELP

[ELAINE7925]

I Am Driving A 92 Bronco And I Am Having The Same Type Of Problems, Were You Able To Get Some Help?

[fordin K]

did you guys notice if black smoke exiting? when was last tune up ? is it sputter like a misfire or fuel cutting out like dirty filter ? need more details

[Truck]

21 (and 14) years later...still have the catalytic convertors? Those are designed to clog after so many miles. When my Tempo's filled up, I couldn't drive uphill more than 30 mph. Which sucks, 'cause I live in the hills.

[POdFordOwner]

I've got a b2 with EFI. It will misbehave when driving after first starting up, sometimes it bucks, sometimes it just looses power (it looses it smoothly, and then gets it back like a switch has been fliped) playing with (or tapping) the gas pedal fixes it, but the problem will come back 3 seconds later. what confuses me is after 5 or ten minutes of aganising driving, it will go away and run like a top (except then when I put it in neutral or park, it stalls) but if I shut it off, and start it back up (even a few minutes later) it will run like crap, and for longer (maybe because the engine is hot). While it's running bad, it can be corrected for a few seconds by turning off the key, then turning it back on.

It also makes black sooty exhaust while running bad

If started and idled it will often idle quite well, but I can move it twenty feet, and it will start running badly, and while it was idling badly I tested the fuel, and the spark systems:
It has good spark, the timing is not being adjusted to hell by the computer because removing the spout connector dosn't help. The fuel pumps are putting 35-40psi to the rack, and a testlight shows the computer is firing the injectors (though maybe not at the right time). I put power to the injectors, and they all click. computer connector looks OK. Oh yea, and unpluging any one cylinder dosn't help.

replaced parts:
sparkplugs - wires - distributer cap - TFI module - coil
TP sensor (computer code said too low) - air filter - fuel filters
fuel pressure regulator -

continuity tested:
computer ground - tfi ground - coil pulse wire
wire from computer to injectors
PIP input wire

testlight'd:
positive to coil, and injectors
injector test plug (on passemger fender next to relays)

sorry for the life story, but this is a complicated problem (at least for me). the only things I can imagine causing this would be the computer, some kind of fire in the throttle body burning up the gas before the engine can use it, or maybe the injectors are periodically being clogged by crap from the fuel rack. None of thiese hypotheses satisfactorily explain the fact that it improves with run time, but is worse if hot (seems to be worse if parked in the sun too), and after (and only after) it gets over running badly, it stalls when put in park.

do they test EEC-4 computers at autozone?

anybody have any ideas?

thanks,
-PO'd Ford Owner

[POdFordOwner]

Update: I bought a EEC-4 computer for a 88 b2, plugged it in, other than idling a little funny (probably because it's learning, o2 sensor is unplugged, and the engine is still full of carbon) it hasn't acted up since.

WOHOOO!!! (this is me jumping up and down)

If anyone has similer problems (sometimes runs shitty despite having fuel, injector pulse, and spark) if it runs shitty during "warmup" then clears out (like mine) then while you are driving (in gear) turn engine off, then on quickly (don't try to crank it, it's still running eventhough the tachometer drops to 0) then drive for a few more minutes, if it starts running shitty again, try a new computer. If it dosn't do the "warmup" thing, then try shutting it off for a second (while moving in gear) while it's running bad, if it clears up for two or three secs after turned back on, it is probably the computer.

[martylephew]

Check the MAP for proper function and connection. I experienced the same problem. I went through the normal trouble shooting excercises. I then started the wiggle and tapp method. I found a broken wire on the MAP connector, it appeared someone had cut the wire in an attemp to check the electrics. (it only took 3 weeks to find?!?!?!)