Engine Misses above idle

[deadbeat]

Working on a 1997 k1500 5.7, put a distributor cap and button on a 3 weeks ago because of a miss and it has ran fine until yesterday. I had pulled codes on it a couple weeks ago because I bought a new scanner that wouldn't connect to the ECM on my 1997 so I thought this would be a good one to test to see if it was the scanner or my truck. 3 codes then, P1345,P0157,P0140 were on it then and still are. I changed the distributor cap and button again, plugs, wires, and coil/ignition module and it is doing the same thing. I am buying a fuel pressure tester today, but when I pushed the schradar valve in the fuel only went maybe 3 inches high. My question is, since the truck cranks up perfect and starts quick, could this be a fuel pump issue. I just imagined if the pump died it would not start, and if the pump was weak the injectors wouldn't open, once again not starting.

 

[deadbeat]

Key on fuel PSI was 54, running at idle was 48, revving up went to around 44 - 46. I think it is the fuel pump. It would hold the key on fuel pressure and not drop.

 

[Supercharged111]

How's the filter?

 

[deadbeat]

I changed the fuel filter before I checked the pressure.

 

[deadbeat]

I put a new Delphi fuel pump assembly in today, still acts the same but I don't have access to a fuel pressure gauge. When I hit the schradar valve on the intake, it seemed very week still. Could this be the spider, if so, how do I check it?

 

[Supercharged111]

Would more likely be the regulator, but replacing the regulator only is risky since the spider is such a POS.

 

[deadbeat]

How can I diagnose that, what would be the Key On fuel pressure, low? What about engine running fuel pressure? The book said 60 - 66, is that key on not running and running? What about revving up?

 

[Supercharged111]

60-66 is measured engine running, vacuum line disconnected. You can achieve the same effect by cracking the throttle wide open engine running.

 

[deadbeat]

I didn't disconnect ?vacuum line, not sure which one to disconnect? I did pour water around the intake to check for leaks, nothing changed.

 

[Supercharged111]

I didn't disconnect ?vacuum line, not sure which one to disconnect? I did pour water around the intake to check for leaks, nothing changed.

I'm a dumbass. No vacuum line, it's all internal. Just watch the gauge pressure rise from an idle to bog throttle crack.