Alright... finally bringing my problem to a real forum outside of Facebook in hopes I can get a answer or point in the right direction.

2001 with the NV4500 trans

Picked this truck up last summer and it's been nothing but problems and money since then. The current issue which also happens to be the best state the truck has been in since I bought it, is a weird idle blip that comes and goes where the truck sounds like its cammed. Ive noticed it seems to be getting worse now that the temps are warming up and occurring more frequently. It also seems to occur when coming to a hard stop. If I have the right conditions where I can really ease the truck to stop it doesnt seem to do as much, but again its began doing it more frequently with the temps warming regardless of how hard or easy I stop the truck.

Now as for the work thats been done and parts replaced in the last 8 or so months, here it goes: VP44 was new when i bought the truck. TPS replaced, and voltage was good when last chcked a few months back. New camshaft position sensor. Brand new FASS 165 lift pump, pressure output is good. New alternator, clutch position switch, and trans relay. All new battery cables and terminals, grounds all cleaned and checked. Rear speed sensor was also replaced. Trans was rebuilt beginning of last fall with new clutch and flywheel.

When I first got the truck it had a bad surging and stalling issue, which after two different diesel shops, along with myself pouring over the truck this is the best condition its been in. It no longer stalls, or surge, but this dang idle blip just rubs me the wrong way after all the time and money ive put into this thing lol...

This past weekend I did find two fittings for the return line off the VP44 were loose which I got tightened up. The tank has also been sumped, and the original pressure and return lines are still in place, which i noticed this weekend the pressure line is just laying along the frame rail uncapped, not sure if this would have any effect, i doubt it would. Theres no tuner on the truck. Aside from the idle blip it drives normal, no hard starts, or any other issues.

Im wondering if its an ecm problem, but before I spend the money im wondering if theres any stones I havent turned yet. Thanks in advance if anyone has any ideas!

 

Could you post a video of the 'idle blip'?? Not quite understanding that one.

 

ill have to try and make one later this week. just think of how one of these trucks sound when its cammed, and thats how it sounds. Maybe idle blip is a bad description. Itll last a few afew seconds, if i cycle the clutch and pull it in and out of gear it seems to bring it back to a normal idle.

 

So, a 'lopey' idle? Isn't that pretty normal for an inline six diesel??

 

Does it have a tuner?