Fuel system issues?

[chip2tx]

Ok guys 98 disco 1 with 4.0. Ran great last night set over night and then suddenly developed slow start, extended cranking. Very bad stumble off idle and will die every time you come to a stop and start to accellerate again. New plugs and wires about 3 months ago. plugs are clean. New fuel filter today but old on was about 6 months old and seamed ok. Havent checked fuel pressure yet on tonights list.
What else should I check I think the fuel pump is giving up but it does run so Im not positive

 

[oly02]

Fuel

Try looking at the throttle body for air leaks or dirt. does your disco idle at the same rpm normally or does it change from time to time. I had this problem and it turned out to be a split in the vac line elbow, replaced the elbow fixed hard starts, stumbles on acceleration and fluctuations at idle

 

[chip2tx]

Has had idle issues since engine change about 6-8 months ago need to have idle air calibrated but cant find anyone locally that has comp capable of this. Engine did sound like it had a vacumn leak recentlly but I haven't been able to find it I replaced fuel pressure regulator vacumn line. Have done normal vacumn leak checks but nothing showed up. This evening I Checked fuel pressure and pump. The pump runs about 2-3 sec at key one and builds 32-33 psi at fuel rail. Enginwe will start and run about 5-10 seconds then stumble and die. Fuel pressure drops to below 10 psi and pump not comming back on til key is cycled off and back on. Any ideas

 

[chip2tx]

Also forgot to add I tried a different mass air sensor and throttle and idle valve clean and working but normally idle is around 1000 rpm since engine swap.

 

[joey]

How many miles on the Disco?

 

[chip2tx]

170,000 on most things the long block has about 135,000

 

[Disco Mike]

Any check engine light/codes?
You will need to get the IAC checked and recalibrated for starters, then if any other issues, deal with them.

 

[chip2tx]

no codes idle issue has been that way since engine change 6-8 months ago . But now it wont run enough to get it out of the garage much lesss drive it 2 hours to somone who has comp to calibrate iac

 

[joey]

Sounds like a bad fuel pump to me

 

[chip2tx]

Swapped fuel pump today steady fuel pressure at 35 started and run good just drove 30 or so milews. seems to run smoother also. Strange that original pump would power up and pressure to 35 but would not retain it with engine running