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dead-spot in acceleration

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Old 03-24-2005, 07:17 PM
FTK560 FTK560 is offline
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Exclamation dead-spot in acceleration

I have a 1986 Ford Bronco II 2.9 auto. The problem is when accelerating I have to accelerate slowly. As long as I push the pedal slowly I can get up to 65 or 70 mph, but if I push hard at all it has a dead spot. Pushing harder just makes it worse. It doesn't just do it on take off, if I am cruising at 45 mph and want to be at 55 mph, I have to do it slowly, and not push too hard. I have changed throttle positioning sensor, EGR valve, fuel pressure regulator, coolant temp sensor, map sensor, oxygen sensor, fuel filter, and rear fuel pump, new tune up, plugs, wires, and distributer cap. Any ideas? Thanks in advance.
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Old 03-28-2005, 02:35 PM
tomw tomw is offline
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Pull the codes?
Leaky intake manifold?
Fuel pressure checked?
The MAP and TPS tell the computer to jazz up the injectors when you push on the gas pedal, just like an accelerator pump in a carb. Something is missing... either the TPS needs to be adjusted, the fuel pressure or flow is low, the MAP is whacko, or rats, just had a senior moment.
Any way, you are not getting the.. AHA, injectors are plugged up and just can't flow the fuel. (brain kicked back in) ... proper fuel flow to make up for the 'lean' caused by opening the throttele.. air will accelerate better than gasoline, so you just add some extra to 'adjust' for the flow properties. That's why you see the puff of black smoke when people accel onto the freeway, or kick-down to pass other vehicles..
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