Lacking power
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Freshman User
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Lacking power
My 94 bronco351 seems to be driving on good and bad days. Sometimes i'll drive it and it will seem slugish on the gas and it appears it shifts differently to. Other times im driving it, it will be real peppy and ill churp the tiresfrom a stop if i floor it. I dont know why it does that and it will randomly change during my driving to. I asked that same questions awhile back and i was told it might be the spark timing so i checked it. It was slightly off but nothing that would be too dramatic. But it didnt fix my problem.
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
Atmospheric conditions will affect the amount of power you have. High heat and humidity will greatly cut power. The condition of the electrical grounds and generating system on your vehicle, as well as the condition of the air and fuel filters will also affect performance. Basically everything matters to a certain extent, including the quality of fuel you happen to be burning at the time. Problems like this are the hardest to track down because it could also be a sensor that is failing but has not yet gone far enough out of spec to be noticed by the computer. Speaking of the computer, have you pulled the codes?
Freshman User
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I'm experiencing pretty much the same thing. 94' F-150 4x4 If outdoor temp is ~70°F. The truck runs like a raped ape (will chirp the tires). Very responsive to the throttle.
If it's colder or hotter out, there's a very slight rattle that can be heard. Throttle response is very sluggish, noticable power loss.
I've checked 2x and it's not throwing any codes. Replaced cap, rotor, wires, Air cleaner, & plugs. Added fuel inj. cleaner. Trans. fluid & filter changed.
Only other issue I have is that the truck takes FOREVER to blow out heat. (will get some warm in about 20min. but, it takes about an hour to blow HOT air).
Any ideas??
Respectfully,
Automatic
If it's colder or hotter out, there's a very slight rattle that can be heard. Throttle response is very sluggish, noticable power loss.
I've checked 2x and it's not throwing any codes. Replaced cap, rotor, wires, Air cleaner, & plugs. Added fuel inj. cleaner. Trans. fluid & filter changed.
Only other issue I have is that the truck takes FOREVER to blow out heat. (will get some warm in about 20min. but, it takes about an hour to blow HOT air).
Any ideas??
Respectfully,
Automatic
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
Sounds like it could be a problem with the intake air temp sensor for both you guys.
The no heat in the cab is likely related to the heater core assembly. I have flushed cores before with the garden hose. Just disconnect the hoses at the firewall(under the hood) and push water back and forth through it. If you get a bunch of gunk out, or very little thru flow then that's your problem. There is also a vacuum actuated door the moves over to block cold air when you switch to heat. If this is not moving(usually due to a broken vacuum line) you won't get much heat either. You have to remove the glove box to access the heater core assembly from inside the cab.
The no heat in the cab is likely related to the heater core assembly. I have flushed cores before with the garden hose. Just disconnect the hoses at the firewall(under the hood) and push water back and forth through it. If you get a bunch of gunk out, or very little thru flow then that's your problem. There is also a vacuum actuated door the moves over to block cold air when you switch to heat. If this is not moving(usually due to a broken vacuum line) you won't get much heat either. You have to remove the glove box to access the heater core assembly from inside the cab.
Hotshot
Joined: Jul 2002
Posts: 14,285
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From: Bend,OR
if that coolant sensor was bad it would throw codes. you might have a bad tstat and if your rig has some miles on it i would replace with the stock 195*. have you replaced the fuel filter? whats your timing set at? what kinda plugs are you using
FTE Legend
Joined: Jun 2006
Posts: 31,930
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From: Ottawa, Ontario
I had a no-heat problem last winter and changing the heater core only made a small difference. It was worse on really cold days than mild days, I would only get slightly warm air out of the vents if the air temp was below -10C. Turns out the thermostat was stuck open.
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Freshman User
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Truck has 80,000 miles on it. Bought it last year with 66,000. Been like this from the start.
I'll check the thermostat first as it's the least $$ to repair. I've got a brand new heater core that I can install as well.
Running Motorcraft plugs in it. I haven't changed out the fuel filter but, it doesn't run like a lack of fuel issue. Best way to describe the power issue: good days= no engine noise (scarry quiet), touch the gas- it goes NOW!. Bad days= very slight rattle on acceleration (gotta have the radio off, windows up to notice), acceleration is best described as doing 20mph in 4th gear and then trying to accelerate quickly.
Trans is E4OD - when I had the service done to it they said it was functioning fine.
Thanks,
Automatic
I'll check the thermostat first as it's the least $$ to repair. I've got a brand new heater core that I can install as well.
Running Motorcraft plugs in it. I haven't changed out the fuel filter but, it doesn't run like a lack of fuel issue. Best way to describe the power issue: good days= no engine noise (scarry quiet), touch the gas- it goes NOW!. Bad days= very slight rattle on acceleration (gotta have the radio off, windows up to notice), acceleration is best described as doing 20mph in 4th gear and then trying to accelerate quickly.
Trans is E4OD - when I had the service done to it they said it was functioning fine.
Thanks,
Automatic
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Freshman User
Joined: Aug 2005
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Thanks Kemicalburns-
I've got to bring it in for emissions testing so, perhaps that will pinpoint to a Cat. Convt. issue. I've occassionally noticed a rattle coming from underneath the truck at idle when I get out. Only happens occassionally.
Respectfully,
Automatic
I've got to bring it in for emissions testing so, perhaps that will pinpoint to a Cat. Convt. issue. I've occassionally noticed a rattle coming from underneath the truck at idle when I get out. Only happens occassionally.
Respectfully,
Automatic
