1987 F150 4.9L hesitate/sputters while accelerating
08-06-2015, 08:34 AM
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1987 F150 4.9L hesitate/sputters while accelerating
I tried looking at some common problem threads but received an error when I tried so I figured I'd write a new one.
I have a 1987 F150 with the 4.9L engine 4x4. For a good while now it would hesitate under light throttle. If I would give it a little bit of throttle it would stop and run perfectly fine. Recently it started hesitating in all ranges of the throttle. It starts and idles perfectly fine. It seems to To rev up fine without sputtering so I'm thinking it's only while I'm driving. It doesn't happen all the time. Some days I'll drive 20 miles and it won't hesitate at all. Next day it'll sputter within the first 3 miles. I've recently changed my spark plugs (double checked the gap at 44), plug wires, distributer cap, rotor, throttle position sensor, and the oil. The last thing I replaced was the throttle position sensor. After I changed it the truck seemed to run great for about 30 miles. Started sputtering really bad driving up the mountain. Just before I replaced it I did put gas in my truck while they were filling their tanks up. My thought was maybe I sucked up some of the sediment they were stirring up filling the tanks. Then going up the mountain it forced it all into the rear of the tank into the pump. Just a thought. Anybody have any ideas?
I have a 1987 F150 with the 4.9L engine 4x4. For a good while now it would hesitate under light throttle. If I would give it a little bit of throttle it would stop and run perfectly fine. Recently it started hesitating in all ranges of the throttle. It starts and idles perfectly fine. It seems to To rev up fine without sputtering so I'm thinking it's only while I'm driving. It doesn't happen all the time. Some days I'll drive 20 miles and it won't hesitate at all. Next day it'll sputter within the first 3 miles. I've recently changed my spark plugs (double checked the gap at 44), plug wires, distributer cap, rotor, throttle position sensor, and the oil. The last thing I replaced was the throttle position sensor. After I changed it the truck seemed to run great for about 30 miles. Started sputtering really bad driving up the mountain. Just before I replaced it I did put gas in my truck while they were filling their tanks up. My thought was maybe I sucked up some of the sediment they were stirring up filling the tanks. Then going up the mountain it forced it all into the rear of the tank into the pump. Just a thought. Anybody have any ideas?
08-09-2015, 06:10 PM
#6
Test your fuel pressure with a gauge. You should have close to 60 psi (your truck runs at 45 to 60 - under 45 it doesn't run worth a damn.
v8's run at 30 to 45psi. It's possible you may have the wrong pump in there.
Would also be an idea to test the TPS. I know it's new but if you don't test it you can't eliminate it - not all new parts are created equal. You did use a Motorcraft TPS of course.
v8's run at 30 to 45psi. It's possible you may have the wrong pump in there.
Would also be an idea to test the TPS. I know it's new but if you don't test it you can't eliminate it - not all new parts are created equal. You did use a Motorcraft TPS of course.
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08-18-2015, 03:30 PM
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OK took truck to the garage and they said I put the wrong plugs in it. I put double platinum in thinking they were better but apparently my truck doesn't power them all too well.