stiff/sticking pedal, weird idle, bad throttle response, wacky tps readings...

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gatorskinseats5

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truck runs good for the most part til sometimes it decides to screw around with a stiff pedal, sluggish throttle response, throttle will stick and then let go and engine will die. even had a weird tick-tick-tick at times. any ideas? also whatever it is doing is causing the throttle position sensor % to bounce around with no influence from the pedal, and my transmission doesnt wanna shift properly. when it doesnt do this it runs good.
 
I would first check tps voltage with the truck not running, and make sure the linkage is all free moving.
 
I'd say tps, then the linkage and returns springs.


Misspelling courtesy of my fat fingers...
 
ok, i am able to check tps readings from my laptop on my pcs and sometimes it stays at 0% with no influence of the pedal and then sometimes it bounces around without even touching the pedal. the engine is kind of surging in a way, then if you rev it the pedal is stiff and it will most likely fall on its face and die once you let off the pedal. it all started as i was driving it and it just started losing power and the pedal was sticking making stopping a bit tougher. ive been having fuel and prime problems out the ass though, just deleted the fuel heater and cleaned the pre filter and itll still do this sometimes. when the tps start fluctuating on its own, the transmission makes shifts at speeds that it shouldnt, and that makes it tough to drive too. before i did the fuel heater delete the system would unprime after an hour of sitting with no leaks. i still have not been able to test how long it stays primed with fuel heater gone but i also left it alone last night after it started acting up.
 
i am now deleting the mech lift pump and using the 7.3's lift pump with a regulator for fuel. i needed a better fuel line set up anyway as the fuel system kept coming unprimed so an air leak somewhere that the fuel heater delete didnt fix. the fuel lines are old broken and jenky anyway.
 
What year is your truck?

The way the engine runs and idles is not connected to the TPS unless the TPS has seized up or failed in some way that it's not allowing the linkage to return properly.

What PSI are you getting from the 7.3 pump?
 
the 7.3 pump is capable of 80 psi or so. i dont have a fuel pressure guage but it ought to be no more than 35 psi. even after the fuel system swap its still doing it. when it gets hot and up to running temp it starts surging and wanting to die if you give it throttle and let it back down to idle. the pedal will also get stiff and ill have to push the pedal more than usual to get the fuel i need to get going so even higher tps percentage with less power = wacky shifting. I noticed last night there was a delivery valve holder loose, and i tightened all the injectors into the head cause it looked like there was some fuel comin from the base of em. after doing all that i took it out and it didnt skip a beat, but today its doing the same thing again. fuel pressure does not seem to be the issue but it sure seems starved of fuel. This only happens when it gets to running temp. the linkage doesnt seem to be binding either as i was fiddling with the linkage and throttle and made sure it was moving freely while revving it and still have the same problem. when its doing this it will also try and rev higher than it should for the amount of throttle you give it, then it falls on its face and dies or will barely catch itself to stay running. None of this makes sense as it only does it after its been running for a little while, for a good bit it will run absolutely fine with plenty of power, but then it starts doin stupid stuff. im really lost at this point and dont know where to begin from here so im begging for some sort solution.
 
yes i put the 12 valve in it but im sick of it now so im gonna go buy this 215 p pumped 24v tomorrow with a real reference for mileage not just heresay, and be much better off.
 
Maybe I'm just tired, but this dudes posts are confusing the hell out of me.

So, 12 valve runs bad, swap in ppump 24 valve?
 
madmikeismad said:
Maybe I'm just tired, but this dudes posts are confusing the hell out of me.

So, 12 valve runs bad, swap in ppump 24 valve?
Click to expand...

That's the way I read it. I'm guessing he bought a truck that somebody had done a Cummins swap in and it has issues.
 
no i swapped the 12 valve into a 2000 f250 without having it rebuilt or anything. just went by what the guy told me that its got 97k miles and its actin up and not performing how i want it to and ive determined it'd be a huge step in the right direction to ditch the 94 12v 160 pump for a 54 block 215 pumped 24v with an honest amount of miles. even if its a stupid little problem like an air leak still somehow, idc. if i have the same problem with the 24v when i put it in, idc, cause then i know its nothing with the motor for one, and two i have a way more badass motor than before. and im tryin to sell the 12v motor
 
complete engine, will need an oil pan cause the motor i just bought needs an oil pan and also a dipstick tube. motor might come with an hx35 if i dont sell it separate, and no engine fan. motor might already be sold though so we will see
 
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