I purchased a Bronco f/s, has 181K on it. Ne trans, tune up, new clutch, ball joints, shocks, etc, etc, etc, It always idled rough and quit. I drove it back to Indiana for an assignment for my wrk. Upon arriving it was really running rough. The mechanic said my fuel ejectors were fouled up. He cleaned them while in the vehicle. Everything has been running ok since then. Except eng lite keeps going on and off. When I accelerate the light come on, when I back off it goes off. I'm thinking it's a vacuum problem. I have replaced most all of the lines and sensors I can find. Any ideas. Also this ruck has never burned a drop of oil in 7000 miles. However I get 11.6 around town and 13.5 on the road. What can I do to get better mileage. Do I need to replace the sensors? Any ideas. Tx

 

Moved from Introductions forum.

 

A high performance coil can help to burn more fuel more completely and opening up the
plugs gap a bit can ensure more spark is in contact with the fuel charge. A bit of gas
line dryer and some marvel mystery oil wouldn't hurt it. You can remove and use a propane torch to clean the oxygen sensor, put it in the flame for 15 seconds
and wipe it clean, Keep doing it until any bad build up is removed and it is pretty clean
of course it isn't going to be shiny, put antisieze on the threads and reinstall.
You can test it with a multimeter but it is most likely okay if the cel is not lit.
If you do mostly city driving and don't get the truck over 55 for longer than a couple
miles you should get on to the highway once a week and open it up and let it stay at
60 for 3 miles, 70 miles for 3 miles basically you want the motor and everything to get up to operating temperature for a good hour ride or so to get the catalytic convertor
up to temp and all the sensors too so they get a workout, Use it or lose it!!
What size tires? what gear ratio? How is your service schedule? all fluids recently swap
out or are you more the type to leave it until it breaks?

 

Tires 31 X 10.50, 3.55 Gear ratio, I made a decision and flushed out the engine and put in Mobil 1, 10-30 Synthitic. I had been in Indianna and because of the extreme cold I had put in 5 x 30. I am determined to keep a good schedule on this old Bronco and do everything right. I bought it 4 months ago. It now has rebuilt trans, new clutch and slave and new master. New water pump, alternator, EEC, EGR & Sensor, New Idle sensor, New purge sensor, New PVC, Oxygen Sensor, New PLugs, Wire and Distriburtor Cap and Rotor, New Starter, Parking brake assy and cable, New Battery and new stock! Positive and Negative cable assys, New vacuum hose where I can get to!! New fan belt and fan shroud,new valance (looks good with new design) New tail light lenses, Control sensor, connects to EGR, New Tires, New Fuel filter(although it nows needs changing after 6000 miles) Like New rear bumper and hitch (pick a part)
Radio w/disc, basic no frills; Starter solenoid, New Mirrors; Tinted rear windows; New Moog ball joints, bushing etc; Edelbrock front and Bilstein shocks rear, New
front brake hoses; Some fuel valve, And probably some stuff I have forgotten about.
I have not replaced the Diverter valve or the TPS, throttle position sensor, yet! when I got to Fort Wayne Indiana, it was really running ruff. The mechanic said the ejectors were all clogged and so he put some stuff in the engine and cleaned them. It has never ran so good! However the little yellow light came on ( he said it would go away) and I have been trying everything to get ride of it. I finally bough a code reader and hopefully it will tell me what's wrong. It purrs like a kitten compared to when I bought it. when I accelerate the light come on and when I let off of the gas it goes away. Level flight it's ok. I figure its a vacuum related problem that's why I have attacked all of the sensors. It could be a misplace vacuum line so when I get close to the chart on the inside of the hood to read it I will try and follow the lines. I hope I haven't board yo with my plight!! I really like this old Bronco and I can't afford a new truck, and I don't think I want one. This Bronco fits me, my dog and mt bike. My wife won't come near it, around town, although she does like to 4 x 4 in the hills behind our home. I looked all around for a Straight Six and this was the only one I found at the time. I was told this old stand by was a winner. A mechanic in Utah said he could R & R the engine for 3000. That's worth having it around. I am now up to about $8000 on this old friend and I enjoy working on it. Never have worked much on cars and now I am 65 and enjoying the challenge. I am not the type to use it till it breaks. I want a good dependable truck that I can fix. Tx for your help. I'll let you know if the oild change helps the lifter noise.

 

Hopefully all that tuneup stuff has helped with gas mileage. What's it getting now with all the tuneups? You should be getting around 17 - 20 in that thing on the interstate if you drive it nicely. With my old never rebuilt carbed '81, I can still get into the 20s.

The 300 in a Bronco is a beautiful thing so that's cool that you actively sought one out. You won't be disappointed. Have you gone through and replaced every vacuum line from front to back? You can never go wrong with that one. I usually bring that one up because it's the last thing most people do and with a new engine it should be the first. I had more problems than I can count disappear after I finally got around to replacing all my vacuum lines after two years of owning it.

 

It sounds like you replaced alot and doing that can cause problems but it it already
done. Try running 2 bottles of heet and 2 of iso heet on 1/2 tank until you get to
about 1/8 tank then refill with fresh gas and some marvel mystery oil. It will ensure
you don't have water blocking an injector and Mmo will keep the fuel pump lubed.
I have the mity vac hand pump and use it to pull a half to full quart of trans fluid
out every oil change, it may be ocd but with the price of a tranny it is cheap insurance
I like the idea of having fresh additives and fluid every 5k. I have a hose as long as
the dipstick and put it in and you can use a old gatorade bottle as the catch bottle
or just do 4 oz at a time. I also use it to empty the brake resovoir then refill it with
fresh fluid before bleeding my brakes(using the vac pump for that too) that way I have
fresh fluid all the way throught the brakes not a crappy mix of old and new. I also
use it to drain my rear end without breaking the gasket why risk a leak? Just suction
it out, add a 4 ounces suction that out then refill to spec. http://www.mityvac.com/
Have you checked the timing? You have to pull the spout connector to adjust it or
it will have a screwed base timing and that can cause hot running and bad economy
the computer can only adjust it so much and it needs to be close to the base for a
starting point. Replacing parts wholesale is against what these forums are about if
you are having running problems you should post up here and see what people tell you
there are many things you can test with a $15.00 multimeter and that will save you
lots of money down the road.