no acceleration at wot
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Junior Member
Joined: Sep 2002
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From: Vale NC
no acceleration at wot
I have a 2000 f150, 5.4l, automatic, with 170k miles. I was cruising along about 65 the other day, went to pass a car, kicked the passing gear and the truck fell on its nose. The engine sounds like its sposed to but it does not accelerate, it doesn't miss or anything. I changed the plugs, cleaned the air filter, but i still have problems. The truck starts and runs fine i just dont have any acceleration at WOT. Any suggestions??
Technical Article Contributor
Joined: Dec 1997
Posts: 9,417
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From: Windsor,Ontario,Canada
Faulty TPS? With the key on using an ammeter voltage at the middle wire. Connect + terminal to that wire and negative to ground. I use a paper clip shoved into the connector. It should show >4.5 volts at WOT.
JMC
JMC
Senior Member
Joined: Jul 2004
Posts: 6,200
Likes: 39
From: Easton, Pa.
Without anything to go on but the thoughts of what would cause your problem, lack of fuel volume is one area.
Usually an aggressive fault will set a code and light but there are exceptions.
Recheck you work area to see if something has been disturbed and not noticed, like the mass air meter or its duct work.
Good luck.
Usually an aggressive fault will set a code and light but there are exceptions.
Recheck you work area to see if something has been disturbed and not noticed, like the mass air meter or its duct work.
Good luck.
Junior Member
Joined: Dec 2011
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engine goes flat at wot
2000 f150 5.4
truck idles and starts good. runs fine unless you push the throttle down too far (usually over halfway down) i can run 75 on freeeway with some acceleration as long as throttle doesn't open too much. when i push too far down the trans downshifts or comes out of lock up and engine just begins to slow down. it doesn't go dead just slows down like no fuel but runs so good at high speeds . cleaned maf with no change. got 4.68 volts on tps middle wire at wot. is that too high? is it enough out of range to cause the problem? at a loss . changed fuel filter twice.
truck idles and starts good. runs fine unless you push the throttle down too far (usually over halfway down) i can run 75 on freeeway with some acceleration as long as throttle doesn't open too much. when i push too far down the trans downshifts or comes out of lock up and engine just begins to slow down. it doesn't go dead just slows down like no fuel but runs so good at high speeds . cleaned maf with no change. got 4.68 volts on tps middle wire at wot. is that too high? is it enough out of range to cause the problem? at a loss . changed fuel filter twice.
Senior Member
Joined: Apr 2004
Posts: 13,679
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From: missing Texas...
2000 f150 5.4
truck idles and starts good. runs fine unless you push the throttle down too far (usually over halfway down) i can run 75 on freeeway with some acceleration as long as throttle doesn't open too much. when i push too far down the trans downshifts or comes out of lock up and engine just begins to slow down. it doesn't go dead just slows down like no fuel but runs so good at high speeds . cleaned maf with no change. got 4.68 volts on tps middle wire at wot. is that too high? is it enough out of range to cause the problem? at a loss . changed fuel filter twice.
truck idles and starts good. runs fine unless you push the throttle down too far (usually over halfway down) i can run 75 on freeeway with some acceleration as long as throttle doesn't open too much. when i push too far down the trans downshifts or comes out of lock up and engine just begins to slow down. it doesn't go dead just slows down like no fuel but runs so good at high speeds . cleaned maf with no change. got 4.68 volts on tps middle wire at wot. is that too high? is it enough out of range to cause the problem? at a loss . changed fuel filter twice.
lack of maintenance???
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From: Utah
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Junior Member
Joined: Dec 2011
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got a manifold (intake ) leak so i am going to change that and go over all work areas and recheck tps . lso have a 2005 5.4 doing the same thing and am changing teh plugs first. broke two and waiting for tool to remove pieces but the 2000 lariat is biggest problem since it is my work truck. second time i changed teh fuel filter it was clean. not sure how accurate the voltmeter is. it shows 4.68 at wot. i'll change it when i change manifold and see.
thanks for all the replies.
john
thanks for all the replies.
john
Junior Member
Joined: Dec 2011
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2000 lariat 5.4. put on new intake, new tps, and clenaed throttle body. put everything back together and it would hardly idle but good wot reponse. ran better than it has for a long time. but woulddn't idle. finally found that i had the egr vacuum line plugged onto something on the left fuel rail and tthe vacuum line that goes to it plugged onto egr valve. so ireversed them and it idled fine but lost wot . it runs good until wot and it just goes flat. it doesn't die, it downshifts but won't accelerate.
it has new fuel filter.
i tried putting the lines back on wrong like they were at first when it ran fine but that didn't help.
the only clue may be that when it ran good at wot the engine was not fully warmed up.
i am at a loss.
help
it has new fuel filter.
i tried putting the lines back on wrong like they were at first when it ran fine but that didn't help.
the only clue may be that when it ran good at wot the engine was not fully warmed up.
i am at a loss.
help