Good Day all ,

I did search a lot before asking but I could not find.

My truck is stock and I has boost / fuel pressure and exhaust temp gauge.

So for the last 2 year my truck was always cutting fuel/power without me letting the gas pedal off. it was not noticeable physically but I could see it on the boost gauge , it was maintaining 4 PSI and then dropping to 2 and back up to 4 on a flat road. As soon as I was turning the cruise control on it was going away. problem solve. I'm always on CC.

Now since the last 6 month, my truck don't get dead pedal effect when CC off, but as soon as I turn the cruise control on, my truck start accelerate way pass the speed which was selected and then it slow way down  the speed selected again. So it is hunting very bad. After 10 minute the engine goes to idle so I jump on the clutch , tap the go pedal few time and the power is restore. I did a 12 hour round trip and it did that 5 time every time I use the CC so on the way back I did not use CC so it was fine. But I got a 224$ speeding  ticket!

My question now , 

would it be cause by a slowly degrading TPS  , I have the truck for 6 years now and I notice the hunting 2 year ago a while after I installed boost gauge,

when a TPS goes bad does it goes bad fast or it can take a very longue time to finally go so bad that you can not use the truck?

 

would it be coming from AC noise from the alternator that cause the CC to malfunction and a small interference in the TPS that cause the engine to  hunt when no on CC?

 

Thanks a lot

Test for excessive AC noise from the alternator. Bad APPS will typically throw a P0121, P0122 or P0123 code. What your talking about sounds like AC noise from the alternator adding noise to the Rach signal creating throttle issues. I have the AC noise test in the articles in transmission section. Typically this shows as torque converter issue on autos. On manuals its just like you said.

Thanks for the fast reply,

I already read your post on AC and torque converter. I'm at work now but can wait to go home and test drive my truck with Alternator fuse pull off to see if CC is acting funny still. 

 

Remember to pull the field lead too. The AC noise will continue to be produced and jump into the positive to the ground wire headed for the ECM.

 

Alternator charge lead on top and the ECM and VP44 ground on the bottom. 

Not to change the subject.... Mike, is that picture taken when you did the W-T grounding mods?

 

That mod does so much good, I had to do it to both my 2nd gens. Both showed great improvement in lower AC ripple, being that it was cut to less than half what it was.