Help needed- intermittent throttle issue

[Fordtruckfan89]

2003 4.0
When I go to accelerate from a stop, sometimes there's a delay from when I push the pedal where the engine speed won't change for several seconds (15+). It doesn't seem to matter how hard I push it. And it doesn't always do it.never has issues once moving. I've ruled out a couple possible causes but not sure where else to look, looking for suggestions
Things I've checked/tried with no difference

Good fuel pressure (idle and acceleration)
Cleaned/replaced maf
Replaced/checked TPS
Plugs (motorcraft) and (Taylor) plug wires were replaced within the last 6 months.
Engine has 20in/hg of vacuum at idle.

 

[Fordtruckfan89]

so no one's experienced a intermittent throttle delay on a 4.0 sohc here? Running out of things to check

 

[fosterzcj]

Is the sensor in the pedal going bad?

 

[JEastonjr]

what is the actual fuel pressure.
scan tool to do a throttle relearn.
actual MAF number.
what's the O2s doing.
This could be a long one.

 

[lincolnlocker]

2003 4.0
When I go to accelerate from a stop, sometimes there's a delay from when I push the pedal where the engine speed won't change for several seconds (15+). It doesn't seem to matter how hard I push it. And it doesn't always do it.never has issues once moving. I've ruled out a couple possible causes but not sure where else to look, looking for suggestions
Things I've checked/tried with no difference

Good fuel pressure (idle and acceleration)
Cleaned/replaced maf
Replaced/checked TPS
Plugs (motorcraft) and (Taylor) plug wires were replaced within the last 6 months.
Engine has 20in/hg of vacuum at idle go to site.

Hello. I need a little help finding out what this problem could be. This problem just started about 2 or 3 packs ago. Randomly if I pull the throttle slowly in my truck will only slightly stutter then nothing for the rest of the throttle. This happens in both forward and reverse and only happens if I slowly pull the throttle it never happens if I just punch the throttle quickly. And like I said it's completely random and doesn't happen every time. Oh and also this never happens with the steering servo it works smoothly all the time every time.

 

[Fordtruckfan89]

After trying to reset it by unhooking the battery, resetting the adaptive learning strategy with forscan lite and reloading the sct tune probably 3-4 times in the last 3 weeks, I tried one more time with the sct tuner (tune has been on it 3-4 years) and it sat overnight and seems to be good now. No throttle issue as of this morning. Makes zero sense to me.

Fuel pressure was 60 with a mechanical gauge, took a screenshot of the readings at idle. Vacuum on engine was 20 in/hg, was wondering if I had a partially clogged cat.

 

[allmyEXes]

TPS ?

 

[JEastonjr]

MAF lb/min
What is it in g/sec? (grams per sec) should be near 4.0 (4.0 sohc)
You my need a better scanner. you need to see what the ECU is seeing. What the throttle is sending to the ECU.

 

[Fordtruckfan89]

Reflashing it one more time seems to have fixed it.

 

[fosterzcj]

Whichever module it is you have to keep reflashing may be going bad if it's not holding info.

 

[Fordtruckfan89]

I can't remember what triggered it to do this, might of been when I changed the battery a month ago. It's about to roll 300k so I'm not surprised if something is going bad.

 

[fosterzcj]

Well 300,000 is quite the distance. You did good taking care if it to go this far.