Rolling up to a stop sign last week my truck lugged down to around 250-300rpm. In park or neutral it idled fine at around 900rpm, but put it in D or R, the tach drops and the engine lugs down.

I thought it was a transmisison problem but after troubleshooting all of last week with the builder and two other tranny gurus I'm thinking it might be an injection pump problem.

Its a 97 180 pump with 90K on it. It has a 0plate and a 3000GSK installed, of which the GSK was in the pump before I purchased it.

The only recent work on the pump was about 2 months ago when I swapped a set of 022's for stock 181's and it ran without issue.

I put in a new fuel filter and checked the fuel pressure which is normal.|
I checked the measurement on the GSK and they matched, but reinstalled them anyway. Since I was dirty I put in a set of bigger injectors and that lowered the idle to were the truck would die with my foot on the brake in D or R. This morning I upped the idle to 1000rpm in P/N and now it only bogs down to around 450-500rpm in D/R.

Any suggestions? I'm about out of ideas other than pulling the pump.

 

Idle is to be around 700-800 in drive with the AC on. So set it to that and see where your Park/Neutral idle is at and find your happy medium.

What kind of injectors did you put in?

 

I know this is going to sound stupid but If It were mine i would try it anyway. Go buy a quart of 2 stroke oil and pour it in with the fuel. See if that helps any. If it doesnt your only out $1.59. Otherwise I would say it is still something to do with the gsk.

 

I'm maxed out on upward movement on the idle adjustment, thats all the idle I can give it.

I know my TC isnt "tight" enough to draw it down 500rpm on engagement.

Pensacola Diesel Stage2's, $204 off ebay.

 

Stuck rack? That's what happened to the last pump I saw like that.

 

Did it behave normally when cruising in 3rd & 4th?

 

Please explain why this is not a transmission problem. It lugs down in gear. It idles fine in neutral. It is logically a transmission problem.

 

yes, behaved normally any rpm as long as you weren't trying to idle or be below 1100.

 

If you're maxed out on your low idle speed and you're only at 900rpm in neutral, your governor springs might be loose. Could try tightening them a click or two, and try it again. I may be way off base too though.