BroncoII4x4.com

87 BII 2.9 auto 75000 miles runs like crap. starts fine idles great. Symptoms include bogging down under varying loads, sputters a bit, puff of black smoke, then takes off like a bat out of hell... New IAC, no codes, both pumps working, new plug wires,plugs good, new cap and rotor, injectors cleaned, local shop checked all sensors said they were good. When last checked mpg sucked(98 miles on full tank). Everything on it is stock. Any help would be greatly appreciated. Only paid 2000 for it but i can't afford to throw a lot of money into it right now(building new house)

Sounds like you are running rich. I'd check out the fuel pressure regulator. Make sure it's hooked up and working properly.

micah

As Nobody says, you are running rich.

Try:
1.
VERY CAREFULLY check every vaccum line, hose and connection. Chances are the problem is a vacuum issue. This includes replacing your PVC valve (just a few bucks).
2.
Disconnect the O2 sensor by where the Y-exhaust pipe joins the catalytic converter. Never mind the no-codes or shop check of the sensors. My O2 unit was bad with no codes, and disconnecting instantly fixed the problem.

CraigK

thanks guys,

i'll be off work for the next couple of days, so i should have time to check and or replace the above mentioned items

ok disconnected o2 sensor....runs smooth as ever. so how long can you run without o2 sensor plugged in

You can probley run as long as you want. I had mine disconnected for awhile and didn't have any problems. The only thing I noticed was that it ran richer and often at stop lights it would idle too low and die. Once I put a new one back on it ran great.