1990 5.7 running lean

[Rme2513]

I have replaced the o2 sensor and cheeked temp sensor and TPS and knock sensor all working can not figure out why it's still running lean what else is there to look for ?

[txab]

A few things to check:

 

Fuel filter

Fuel pump pressure

Air intake for leaks

[Rme2513]

A few things to check:

 

Fuel filter

Fuel pump pressure

Air intake for leaks

Ok thanks and what do you think about the MAP sensor

[Rme2513]

Put a MAP sensor on it runs a lot better but still might need a filter and pump seams to die out at higher rpms

[Rme2513]

Fuel pump fixed it runs like a champ for 250 k mikes

[txab]