dripley

Lower pressure while cranking is normal. the ECM is doing that. You are most likely loosing the prime in the fuel system. By that I mean air is getting in some where. The return line from the back of the head and the VP is a major culprit. Those two lines join together at a tee back behind the fuel filter canister. I would check those line first.

Very true.

Some folks have to much time on their hands.

A leaky return line us not the problem.

Not sure what you mean by the return line on the sending unit.

Double ouch!!

How I see it. APPS=acclerator pedal position sensor. TPS=throtle positioning sensor APPS is on the the pedal, TPS is on the engine. That being said they both do the same thing, it is just location and how each individual sees it. They might be configured different for the location but do the same thing. After taking mine apart and really seeing it had no mechanical connection to the engine I was a bit surprised. Seems to me dodge was tring to fake us out like the fake oil pressure gauge in the 02's and later years. I have an AD also and it shoul be giving you accurate pressure as long as the gauge is good. What codes are you seeing?

I guess I am trying to understand your fuel pressure. You say your gauge is reading 16 to 17 psi but not sure at the VP. If your gauge is after your last filter thats the pressure the VP is seeing. Is your FP gauge not an actual pressure gauge? Not sure what that means. Codes are important if you have any. If you you dont have a scanner most any auto parts store has them and will be happy to read them for you. Jot them down and post them up. It will help. As far as the APPS vs TPS they are the same. The APPS mounts on the accelarator pedal and the TPS on our trucks mounts to the bellcrank assembly on the intake manifold. They both perform the same function. The APPS started on the 3rd gens I believe.

Did you replace you return lines also? The tee or the connection on the back head can both cause the problem. Also did you have the problem prior to replacing the fuel lines? Anything that lets air into the fuel system can cause it. A slow cranking starter can cause it too.

FWIW the heater treater part I installed came with 9v battery to use for indexing the motor. As I remebr it worked quite well.

When my turn comes itmwillmbe the Quad. Just sound all around better to me, if I can learn to use it.

If you were cruising with clurch engaged an increase in rpm should cause an increase in speed. Mine would increase in speec when I had a very similar issue a while back. My issue was in the wiring with the 5v supply to the sensors. I repaired the bad splice and did the WT ground mod and have been fine since. As stated above, a bad APPS can cause the issue also. Just was not my issue. Run the diagnostics to be sure.

Well pecker head!!

You could pull the connector and see if you have voltage at the connector after bumping the starter. Voltage should be present for 20 seconds or so.

OE style lift pump? When my original went the truck woild not start.

Is your truck stock? Stock there will not be a relay for the lift pump. There is a relay in the PDC for the VP. Swap it for the horn relay or any other that works and see if that helps. The prime of the lift pump at key on is ECM controlled. Does your WTS light come at key on? If its warm out it is only lit briefly so you have to watch closely.

Have you put a scanner on it to check for codes?

The solution???

Did a little looking and the 4500 is 195 vs 360 for the 56000. Thats why I did not think it was cast iron. I have pulled my 5600 a couple times, it is beast. They are both a beast with out a lift and in a gravel drive way.

Is the 4500 cast iron? How many miles on the SB?

I would have to say that 5 to 7 psi at WOT is not satisfactory unless maybe a stock set up. Especially if you were seeing better shortly before. Could be the screens are clogging or the filter. There are different schools of thought on pressure, me personally, I dont want to see less than 14 psi at WOT. The lower pressres could the cause of the bucking @wil440 has been experiencing.

I have had a happen a good while. Fuel filter stopped it the first time. The other times were with in intank pump loosing pressure. I put a booster pump on it and it stopped. The issue is very much as you describe, almost like the engine shuts off for a split second then keeps right on going.

I am a amatuer coin collector. The hunt is fun but for those kind of coins the pockets have to be a bit deep. But the hunt is just as much fun for me.

Put 70+ hours in lasr week a d will cross 40 tomorrow about 1pm. Who is the stoodge?

The biggest mess mine ever made was the tappet cover gasket. Looke like the engine was leaking oil from every where.