Hi guys, for the last few months, maybe once a week or so, I'll be accelerating at maybe 2/3rd power, and the gas pedal will stop working. No lights flash, no nothing. Just like I let off the accelerator and the truck goes to idle. After a few seconds, I can hit the pedal again and it's fine. Yesterday it did it about 3 times in a row, even when just cruising and not accelerating. Today, didn't do it at all. Do the trucks have a TPS that goes bad? I was doing some searching and I found that most people who had problems like this experienced a bunch of flashing codes on the dash. I don't even have a check engine light. It literally acts like I simply took my foot off the pedal.

Thanks in advance!

 

The accelerator pedal assy is comprised of two individual sensors: TPS (Throttle Position Sensor (separate 3 wire connector) and IVS (Idle Validation Switch 2 wire connector just the TPS can be replaced.

Basically, it is a potentiometer.

The easiest way to check it is with a bi-directional scan tool such as AutoEnginuity.

If you don't have access, the way to check it is to disconnect it from the wiring harness. Using a DMM, Set to Ω, connect the leads to the TPS connections.

Three connections:
Signal
5V Reference
Ground

KOEO determine the 5V Reference Wire. Once you know what that is, you WON'T be testing that pin. You will be testing the remaining 2 with the KEY OFF.

While depressing the pedal, you should:

1. Not loose continuity or,
2. see any spikes

It should steadily increase/decrease +/- 5 Ω

You may have to do this process slowly several times to recreate the issue.

The TPS can be ordered separate and is a Dorman Product Line.

TPS Symptoms:

1. Hesitation on acceleration, usually just off idle
2. High idle speed
3. Low idle speed
4. Rolling idle speed
5. Stalling at stops
6. No start (TPS stuck at WOT during cranking)

 

Have you tried cleaning it. Get a can of electrical cleaner and get up in there and give it a good cleaning. Most likely just excessive dirt that needs to be sprayed out.

 

Thanks guys! Since it's extremely intermittent, do you think that it's going to test ok except for that once a week for a split second?

 

If that TPS goes open it will set a code. SES light on and that's a hard code,wont go away when you cycle the key. What engine is in there, the triton? Did you scan it, auto zone will do it for free. just dont buy anything they suggest, I had a 5.4 that did the same thing turned out the MAF was bad. Get back to us.

 

Sorry Dave, I'm posting from the phone and I don't think my signature is showing. It's a 2001 F350 4x4 srw with the 7.3/auto.

 

You dont have a TPS on your truck, it's throttle by wire, Inside your accelerator pedal under your dash is the throttle switch, the pcm reads directly from there, they have 3 separate potentiometers in it, basically for safety, circuit a reads 0 volt to 3.5, circuit b reads 4 volts to .50, and circuit c reads 2.5 to 5.0 volts or something like that, they all have to match to have proper function of the pedal. You really need a scan tool, not only can it throw a code but you can watch the swing and the voltage of the 3 circuits. It may not even be related to the APP sensor. Take a look at the wiring with a flashlight since your feet are banging around down there you could have knocked the wiring or connectors. I have never replaced one in all these years working on the ford diesels. it usually turns out to be a fuel problem, check your ICP sensor or harness, the harness is easy you will know if it needs replacment, the sensor you need the scanner. if you unplug the connector and its wet with oil you need a new one, the best would be to have the scanner on your lap and road test and see what happens if it starts to act up. Thats what I am going to bad ICP, is your oil clean and full, drain the water from the bowl and replace the filter, ever notice it only acts up when your below a 1/4 tank of fuel? Than it's hutch/harpoon mod for you There is alot than can cause the truck to return to idle, scan tool is most important, let Advanced auto scan it for free, but don't buy any parts there.

 

In some of our trucks, the TPS can be purchased separately and replaced without having to change out the entire pedal assembly, but it seems that most are integrally built together and you have to replace the entire pedal assembly. There seems to be no magical trim configuration or manufacturing year by which to determine if yours has a separate or integral sensor. I've looked into rebuilding the integral units, but it does not appear to be a straight forward possibility unless you can replace the original rivets with bolts as part of the process... I still have my last one, but have not taken the time to try a complete tear down & rebuild yet because my bank is out of "round tuits". The Motorcraft part will run about $75 and only takes about 15-20 minutes to change (depending on how much of a contortionist you are). If you have adjustable pedals, the assembly is closer to the $300 mark.

I've gone through the original and one replacement pedal assembly on my truck. The first replacement lasted me about 75K miles. The second replacement unit I'm using now has been holding up fine for several years. Both the first and current replacement units have been Motorcraft parts (NOT aftermarket).

When both of mine started going out, it was intermittent, and the accelerator would simply "drop out" when pulling off from a stop and then kick back in after 1-2 seconds. Might happen once weekly, but it progressed to once/twice daily by the time I changed them out. Same pattern of demise each time. Electronics cleaner did me no good either time.

 

F250, that's pretty much what mine is doing. Very intermittent. Just basically randomly stops working. It does it about once a week, then last week it did it three times in one day. Hasn't done it at all since. I'll take apart what I can and clean it with some rc motor cleaner.

David, what water draining are you referring to? Oil and fuel are good. Fuel is at a half tank. I actually had the elbow break off, so I can't go below 1/8th tank. I need to take the tank down and do the procedure to it. Just trying to get everything else maintained first. Next is axle seals, rear brakes, and parking brakes.