replaced vp and truck runs great but it will idle rough sometimes and goes back to normal. any ideas?

 

no body has had this problem?

 

You might have a APPS/TPS sensor going bad... That would be my guess.

 

My truck has done that too since I replaced the vp. It usually does it after it gets warm, or if I step on it and let off fast. But it runs fine so I'm not worried about it.

 

i have the same problem also, i was told its an injector missfire.

 

Does your rpm gauge represent the stumble or idle issue? Is it a stumble or is it a prolonged idle issue for a few seconds or a couple of minutes?

 

yes the rpm gauge shows it. and it happens a few seconds and goes away.

 

If your injector was miss firing then you need to take them out and have them pop tested and re shimed... Have mine all done for 20$ total and they were off a couple hundred lbs. But the pre/post detonation shouldnt be that big to notice. Check or replace your apps that seems to be you problem. When the apps is bad or going out the sensor tells the computer a low or higher rpm which usually is controlled by your foot. The apps is bolted on to the throttle linkage so its like your foot moving up and down on the pedal. The apps will send that bad signal and the engine will move and adjust constantly following the code... So it might be that or somewhere in the fuel system theres a hickup not gettign fuel somewhere. IDK thats my 2 cents..

 

My idle varies in neutral around 20rpm but it is steady in gear. After it is warm and in neutral, it will stumble slightly if I rev it to 1,000 rpm. It runs great otherwise and no codes.

What do you have for fuel pressure? I have heard that metal shavings from the damages vp can get to the injectors but that will cause running issues all the time.

 

fuel never goes below 16 psi. never heard of the metal shavings getting into injectors before. dont know if its that cause the elec. side of my pump was bad i believe.