Pulsing when braking/stopped

[tgarrisoniv]

i have looked all over and cannot find a similiar issue. my 99 psd (180k) after running at 60+ or heavy acceleration for more than a min will begin to pulse when i am almost stopped/stopped. it will not do it if i am going slow or only going a short distance (red light to red light or something). i thought it could be ipr so replaced it. no difference. When it starts to pulse i can throw it in N and it will stop but as soon as i put it back in D it will be right back at it. It is bad, like hold the hell on to the brake pedal or hit whoever is in front of you. it usually will do it for about 10-12 seconds and then drop rpms back to normal idle. help!!

[tgarrisoniv]

nobody else has had this issue?

[1snakedoc]

what is pulsing? the truck or the motor?

[tgarrisoniv]

the motor. its acts like it may not be getting fuel or the oil pressure is not accurate with the idle. it revs from about 500rpm-1500rpm for about 5-6 seconds and then goes back to idle. also, i got stuck the other night and when it revs up high rpm and then i let off and the tires stop quickly, it shuts off. it did it 3 or 4 times in a row. it always cranks right back up but i really want to fix this issue!!

[late_99_PSD]

Maybe an ICP problem. Its not setting the MIL/CEL? Is it chipped? If so, set it to stock and see if it goes away. Time to get a scanner on it while its doing it.

[tgarrisoniv]

yes it has a 6-pos ts performance chip. i have scanned it and i get codes: P0603, P0605 (both for kam i think because of the chip), P0236 (turbo boost sensor a circuit performance; i have a leak between turbo and down-pipe) and thats it... I have checked icp and unplugged, running no oil comes out. could it still be bad? i will also try running it in stock and see if it still happens. ( i NEVER run it in stock mode) thanks for the tip.

[late_99_PSD]

Yes your ICP could still be bad and not leaking, BUT I would not change it unless you know thats the problem. I would get a good scanner on it that you can read live data so you can see whats going on when it surges. The chip I had on my truck before was tuned for the wrong PCM and would just die, so I wouldn't rule out your chip. Let us know what you find.

[tgarrisoniv]

ok i have a simple OBD2 cheapo scanner. a buddy of mine that owns a diesel shop will let me borrow his live onboard stuff though. will give it a try sometime this week. thanks for the help!