Bryce is right. Mine is a T right before the ip about 6in away. With a mechanical gauge you need to put in a needle valve so it doesnt put a water hammer effect on the gauge and mess it up. Some guys dont like though of having diesel running into the cab for the gauge so you can use a isolator which will use antifreez to the gauge instead of diesel. Without a good lift pump the stock one(ones mounted on the block even more so) After the years of towing and driving they wear out and dont supply good psi and cool fuel to the vp which in turn kills the vp. When they go they will do all sorts of wacky things. You can try and do a apps reset but I doubt its gonna fix the problem.

ok i'll have to get one of them and try it. i planned on getting the edge tuner after all this stuff.. doesnt that measure lift pump pressure?

Yes it does. Some people dont like it as its a electric item that measures everything. So if it were to quit working you dont have anything to look at or alert you that something is high or low. I have the older edge juice in my truck which tells me everything it hasnt gave me any problems but still something you should look at. I think my next tuner after my edge dies will be a quad adrenaline much more customizable.

thats fine. im just stumped on this whole issue.. i will start by ripping out the harness and take it all apart and look for problems there and do a sweep test on the TPS with with ohm meter and if both of them turn out then i can safely assume its the ECM or pump.

i just put a injection pump on my truck and it didnt fix it.

I really can't help you with your problem, but I can relate a story from a cummins owner that had a similar problem. It turned out to be a corroded connection at one of the plugs going to the Vp or ecm. sorry I cant remember which one. The corrision wasn't necessarily visible, The mechanic that was working on just started taking all the connections loose and cleaning them, then he found the one that was causing the problem. And it fixed that truck. After reading your posts this sounds like your already going down that path anyways. good luck.

i got a used ecm today so we will see if that does it.. i didnt pull any of the pin recepticals out of the main plug to the ECM but i checked for continuity from the main plug to the pump connections and other and all checked out. soooo we will see if this does it. ill let you guys know..

thanks barry if i have to check again i will go there.

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went through the wire harness all checked out and replaced the ECU. still the same issue.. only difference is in gear or under load she bogs down then jumps back and lopes a bit. and still no high idle. guess its the pump..