98 6.5 sputtering

[vaughn54]

I have a 98 one ton chevy van with a 6.5 diesel and it has been running rough
when cold and now it misses real bad when engine is cold and still some after it is fully warmed up. It starts right up and idles fine. Has no power under throttle. It has 150,000 miles and 100,000 on block. Dealer replaced injection pump and PMD under warranty one time. It was actually stalling while driving down the road that time.
It has also had the lift pump replaced once.
This is different. Could it need new injectors at 150,000 miles or is it the PMD.
It has to be awfully hot crammed under that dog box compared to a pickup.
If it needs a new PMD I was wanting to mount a remote one with a cooler but with a van you are really limited to space where you could mount it.
It also needs head gaskets. The one on the drivers side is leaking.
Mechanic recommended replacing injectors while he has it torn apart to do the head gaskets.
Does anyone know if the remote PMD cooler from A 1 Customs is a good unit.
It is around $ 550.00 with a new PMD.
I have owned 3 6.2 GM trucks back in the 80's and this one I have had 9 years since new
thanks

[bbtlr3]

Is it throwing any codes? Is it missing under acceleration or at steady throttle? If its not stalling out I would think injectors for an intermittent miss not related to acceleration. If it's missing only under acceleration I would take a look at the lift pump, OPS, and the relay. But if you are already getting the head gaskets done have the mechanic replace the injectors because even if they are not the problem they will be soon if they have 150k on them. Some people say after about 100k they will be on borrowed time. Your miss could be related to the head gasket as well so take care of the bigger issue and see where you are at then. The recommendation to replace injectors while in there is probably well advised IMO. Might save a little labor cost later on.

[vaughn54]

When I started it this morning it smoked a while and idled slow and the service engine light was on as it should be when it does that.
The lift pump is vibrating and sounds like it is pumping.
Could it be working but not enough pressure or fuel flo.
If I change it myself where do I bleed the system. It is a van and different than a pickup.
The fuel filter is under the van by the drivers door, and up under the hood where the thermostat housing comes is a valve where the fuel lines run thru.
I assume I will have to bleed the system off after I change it.
Thanks

[JohnC]

The vendor you mentioned has been banned from more forums than I can count, for good reason (this one included). IMHO, his product is about $300 over priced. His claim of "no failures" is BS.

Check the vendors who support this web site, or those touted on other forums for better products at similar prices.

I doubt if your running problems are caused by the PMD. First thing I'd do is change the fuel and air filters and confirm the lift pump is working correctly. Next, a compression check is in order. If you need head gaskets, the compression may be bad and that likely is the root of your problems.

[vaughn54]

I replaced the lift pump today and it still runs the same. It has good oil pressure and is not using oil. It never runs hot and I have the stock thermostats in it put in by GM dealer.
If I can get it to the dealer I will have a new fuel filter put on. The light is not coming on for the filter. I noticed today when I opened the bleeder on top of the filter after I installed the lift pump there is a plug hanging there not hooked up to anything. There was one hooked up and this other one just hanging. I could not see anywhere it would go. It has a 90 degree end on it about like a small spark plug. I have only had it changed at a GM shop since new. This is on a van and the filter is mounted under the van about in line with the drivers door and has a metal cover around it you have to remove to service it.
I will have the dealer plug his computer in to see what kind of codes it reads out.
What do I have to buy to hook up a laptop to my van to do this myself. I would assume the terminal under the dash is the same for all late model 6.5 TD's. Also does the program list all the codes and what they mean.
Thanks