Many problems 2000 4.6L

[MarkS]

My 2000 Expy 4.6L is giving many problems.
1.) Hesitates on acceleration
2.) Random motor surges
3.) Stalls when accelerating quickly
4.) Stalls at Idle
5.) Shifts erratically

Parts replaced:
1.) Replace fuel pump (fuel pressure at the rail 30psi Haynes says 50psi) after fuel pump still 30psi
2.) Replace fuel filter
3.) Replace IAC
4.) Replace spark plugs

Thank you for any and all input.

 

[outkast]

could possibly be a coil, is there a fuel presure regulator? seems the 30psi is where my concern would be.

 

[DarrinBC]

Have you tried cleaning the MAF yet? I would also check the throttle position sensor voltage.

Darrin

 

[MarkS]

Yes I cleaned the MAF sensor and backprobed the idle control which I replaced.

Today I checked coils and plugs and added dielectric grease. It seemed to run a little better but stills stalls and is nowhere close to 100%. A few COP where not tight.

 

[GaryH2]

4.6 issues

I had a coil pack replaced 2x on my old 02 Expy. Some of the symptoms sound like that (rough idling and so on). Have your coil packs checked out ok?