Throttle Response Issue
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Posting Guru
Joined: Jul 2007
Posts: 1,433
Likes: 2
From: Spring Lake
Throttle Response Issue
Hey guys, for once I'm posting something up NOT about my truck! I got a friend who is having some issues with his truck's throttle response. He's got a 99-04 5.4L that is acting awefully peculiar and I wanted to do some homework before I write a prescription for this...
Pretty much the problem is showing itself in 2 places:
1. More sluggish than it should be
2. Does not properly downshift
I was thinking TPS, however is there anything else that can cause this? My buddy thinks he has a bad transmission, however that doesn't jive in my mind considering it apparently has all 4 gears with no slips. Please let me know what ya think!
Pretty much the problem is showing itself in 2 places:
1. More sluggish than it should be
2. Does not properly downshift
I was thinking TPS, however is there anything else that can cause this? My buddy thinks he has a bad transmission, however that doesn't jive in my mind considering it apparently has all 4 gears with no slips. Please let me know what ya think!
Posting Guru
Joined: Jan 2008
Posts: 2,408
Likes: 0
From: Trenton, MI
More info 2001 F250 with 3.73 in axle.
It have almost 200K miles. We have no idea who was first owner. We think it was MDOT truck for Michigan.
No engine light on.
When I bought. Reverse wasn't work it would stall engine. Change tran oil and filter actually help much. No more stall but old tran oil really bad and burned. It been sit for 3 years.
Engine isn't burn any oil and get 15-16 mpg in City/Hwy/tow.
If you press overdrive button ON it will not downshift. Try manual in 2 gears no respond but 1 gear it downshift.
If you leave 1 shifter. It respond and rpm gauge go up until you shift to 2 then 3 then 4 gears. It work right but will not downshift expect 1 gear.
Before we go. I think shifter cable is out position because I have hard time get in P and make sure truck isn't roll in neutral.
It have almost 200K miles. We have no idea who was first owner. We think it was MDOT truck for Michigan.
No engine light on.
When I bought. Reverse wasn't work it would stall engine. Change tran oil and filter actually help much. No more stall but old tran oil really bad and burned. It been sit for 3 years.
Engine isn't burn any oil and get 15-16 mpg in City/Hwy/tow.
If you press overdrive button ON it will not downshift. Try manual in 2 gears no respond but 1 gear it downshift.
If you leave 1 shifter. It respond and rpm gauge go up until you shift to 2 then 3 then 4 gears. It work right but will not downshift expect 1 gear.
Before we go. I think shifter cable is out position because I have hard time get in P and make sure truck isn't roll in neutral.
Hotshot
Joined: Mar 2007
Posts: 10,101
Likes: 40
From: Pa
I would start with replacing the fuel filter, replace air filter (if paper), clean MAF run some type of fuel injector cleaner. I have been using Marine Stabil every now an them in my truck after seeing how well it works and cleans in my outboard motors. Could also check for any DTCs, however there probably isn't any. In order to throw a code something of fair substance has to go wrong on these trucks.
Posting Guru
Joined: Jan 2008
Posts: 2,408
Likes: 0
From: Trenton, MI
Ok I study while drive.
It very strange.
Overdrive button work right now it downshift and if you manual shift to 2 gear it downshift but if you touch brake and rpm go down to 1000 instead 2,000 until you hit gas it in gear.
Well I will try clean maf.
Would expedition or ecoline or F150 MAF sensor fit?
It very strange.
Overdrive button work right now it downshift and if you manual shift to 2 gear it downshift but if you touch brake and rpm go down to 1000 instead 2,000 until you hit gas it in gear.
Well I will try clean maf.
Would expedition or ecoline or F150 MAF sensor fit?
Freshman User
Joined: Aug 2010
Posts: 39
Likes: 0
try cleaning your throttle body, if not the tps and throttle body is sold as a unit from ford i beleive, check your tps voltage at idle with the iac unplugged, should be just below 1.0 and sweep to 5.0 at wot. Does your car have an electric pedal, because these get pad spots in them too causing acceleration issues
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Posting Guru
Joined: Jan 2008
Posts: 2,408
Likes: 0
From: Trenton, MI
When I bought I did clean Throttle body first thing.
It wasn't too bad. Just minor carbon but our 01 F250 V10 was WORST than that one but only 100K miles that time.
I try clean MAF and reset battery to erase everything. I would say very very little difference in accelerator.
It wasn't too bad. Just minor carbon but our 01 F250 V10 was WORST than that one but only 100K miles that time.
I try clean MAF and reset battery to erase everything. I would say very very little difference in accelerator.
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