Hey guys, new to the forum and desperate someone out there has experienced the problem I am having.

My 88 Bronco II has been to two different mechanics (the first worked on it three separate times) for a fuel/acceleration problem. Initially, it was flooding out really bad and the timing seemed off. I had put new plugs and plug wires on it and had noticed the distributor was loose. The first mechanic timed it, fixed the distr., and replaced the "fuel regulator" something or other. He also put new plugs in it because the old ones were supposedly fouled. He said 90psi of raw fuel was getting into the top end when it was supposed to be 35 psi.

Every day since then the vehicle runs pretty good until I go about 6-10 miles and it gets warmed up. Then it loads up, runs flat, and sputters about mid-way through the rpms. In other words, if you get on the interstate and keep the pedal down it does fine, but if you let off, or come to a stop and then try to accelerate it sputters and puts out a lot of black smoke for 15-30 seconds, then takes off. Idle is also rough, a sort of loping idle.

On the second visit the first mechanic said he replaced the MAP sensor. The third time he essentially gave up on it and said it ran fine when he worked on it, after he let it idle for a hour and warmed up. He said the problem was it would take time for the fuel to "work its way out of the top end".

The second guy said he was positive it was an electrical problem. Checked it out and then said the computer module was bad. That is how things stand now.

My truck runs great except for this problem. I put a new coil on it to no avail. I have put in several bottles of fuel injector cleaner and water on the gas removal stuff. I checked the plug wires myself and they are all connected and good.

Would a bad O2 sensor cause this kind of problem? If anyone on the list has had any experience like this and could offer suggestions, I would be most grateful. If you wanted to visit western NC I could pay you back by showing you some great forest roads and areas to get the tires muddy!

Thanks much.

Orrery in NC

 

Welcome to FTE!!!

I would start by pulling the codes, you can do this yourself, see "pulling eec-iv codes" in the tech info thread at the top of this forum.

Next check the vaccum line to the fuel pressure regulator for gas after it has been running for a few minutes, I know he replaced it but it could be a bad part.

Then retest the fuel pressure.

 

I am having the same problem, With acceleration I mean. I haven't gone to a shop or anything but I definetly want to keep watch and see what happens with yours!
GL

Kray

 

You might want to check your throttle position sensor. My BII was missing, idiling wierd and blowing black smoke. I was in Wisconsin at the time and nobody had one, so I took it off and found some grains of sand or something in there, I sprayed it off with throttle body cleaner, and drove 600 miles home to Michigan with no problems, probably may need one later on but runs fine now.
Shiny

 

About a year ago I had the same problem. It ran fine until I ran at about 40 mph then it would try to stall when idling and blow black smoke when not flooring it. I replaced the O2 sensor and haven't had a problem since. Easy job and I think the O2 sensor went for ~$40.