Lack of Power

[inxy]

89 Bronco 351W - any gear max rpm 2200/2500. Poor accellaration. Top speed 60mph with a two mile level run to get there. Tap on gas light at 40mph and it down shifts. Tran is three speed auto.

Engine is a low mileage (50,000) Ford rebuild.

So far new - ignition module, plugs, wires, cap, rotor, msd coil and fuel filter.

What's next ? What I am I l oking for ? All suggestions are welcome.

Bruce

 

[Big Country]

kind of sounds like my problem. replaced everything you did. working on taking the carb off and cleaning it also checking on the choke thermostat and choke pulloff. both of which regulate the choke plate's position. if it stays closed while you accelerate it might be choking the truck. can you accelerate hard before that? other than that it might be the tranny which is what I am hopong my problem isnt.

 

[Yardape]

The throttle likes to get stuck on our chunks of iron. Un hook the throttle cable and TV cable, also the cruise if you have it. Try and give it full throttle by hand, mine was only getting half throttle. The throttle linkage on the throttle body likes to bends downwards for some reason, Bend this up just slightly, Now try your throttle again. Did that to mine and it feels like I put in a whole new engine

 

[inxy]

Throttle cable does what it's supposed to do.

Further on observations - old plugs looked good, no obvious vacuum leak, starts and idles normal, engine under load sounds normal. Maniford vacuun about 5 at idle and 8/9 at 2500 rpm. No drop off when holding at 2500 rpm. Exhaust pressure under 1 psi at O2 sensor port. Catalytic conv not plugged or exhaust blocked. Been a slow drop off in power over the last 30 days or so and now to did a major increase. The Bronoc is used for city driving and pulls a 16 foot lawn service trailer (about three thousands lbs). EFI equiped.

 

[Seabronc]

Throttle cable does what it's supposed to do.

Further on observations - old plugs looked good, no obvious vacuum leak, starts and idles normal, engine under load sounds normal. Maniford vacuun about 5 at idle and 8/9 at 2500 rpm. No drop off when holding at 2500 rpm. Exhaust pressure under 1 psi at O2 sensor port. Catalytic conv not plugged or exhaust blocked. Been a slow drop off in power over the last 30 days or so and now to did a major increase. The Bronoc is used for city driving and pulls a 16 foot lawn service trailer (about three thousands lbs). EFI equiped.

What size tires and rear gears?

>-

 

[inxy]

Tires are 33", no idea of rear gears. Probably stock. Bronco ran great for a year. Cruise down the interstate at 72 mph @ 2700/2800 rpm.

 

[mbtech2003]

Throttle cable does what it's supposed to do.

Further on observations - old plugs looked good, no obvious vacuum leak, starts and idles normal, engine under load sounds normal. Maniford vacuun about 5 at idle and 8/9 at 2500 rpm. No drop off when holding at 2500 rpm. Exhaust pressure under 1 psi at O2 sensor port. Catalytic conv not plugged or exhaust blocked. Been a slow drop off in power over the last 30 days or so and now to did a major increase. The Bronoc is used for city driving and pulls a 16 foot lawn service trailer (about three thousands lbs). EFI equiped.

i think the vaccume should be around 15- 20 unless u have a hudge cam or other problem others might know better but my engine with a mild cam is around 14-18...... try another port to get a good vacum sorce

could also be tps... throttle posision sensor confusing the computer.

 

[Yardape]

I have 33's on mine, and with a 302 it is a complete ****! When my engine started messing up, I put 31's on just to help the engine live a little longer and better gas mileage for the poor thing. Your truck was designed to run on 28's from the factory, if you want factory performance then put the 28's back on, if you want performance out of the 33's then I advise you to install 4.10 gears front and rear. You customize you sacrifice theres no way to get around it.

 

[inxy]

Finally found the problems - EGR partially stuck open and timing set by a shop was very off - not even close.

Runs great now.

I'll never use that shop again - idiots !

 

[Seabronc]

Finally found the problems - EGR partially stuck open and timing set by a shop was very off - not even close.

Runs great now.

I'll never use that shop again - idiots !

Thanks for the update, I wish everybody would give a final update when they find the actual cause of their problem. That is what makes a forum work. Glad you found it. This may help some other owner with the csame problem /emoticons/[email protected] 2x" width="20" height="20" /> .

Good luck,

>-

 

[caseys 93]

Agreed!