i have a jeep cherokee 87 change plug cap rooter fuel filtre and a have no power. good well but can go fast, long to aceleret

 

No mention of replacing plug wires.

For older engines, never a bad idea to take a compression test on all cylinders. It is a good "snapshot in time" of the internal condition of the engine.

The compression spec for the 4.0 is 120-150 psi, with no more than a 30 psi variation between cylinders.

 

i diconect the fuel pump regulator and its beter but not ok

 

Verify fuel pressure with a gauge. No shortcuts. You should have 31 psi at idle. Then disconnect the vacuum line leading to the fuel pressure regulator (be sure that vacuum line is pulling good vacuum) and the pressure should jump to approximately 39 psi.

A clogged catalytic converter is another possibility. You can verify that with a simple vacuum test. SEARCH the web for the how-to.

 

its ok now its whas my fuel pump