[LTb1ow]

Yea, something is wacky there.

And if the car is running fine, then the horn button messes up idle something is wacky. The pump can run fast, slow, or whatever it wants as long as it maintains 40psi to rail, the regulator will make average FP what you need. So..

A) Your fuel pump is running slow on low voltage and the horn adds normal voltage (too little FP and it gets the OE amount with horn)
B) The horn causes fuel pump to lose voltage and slow down. (normal FP, but horn causes pump to slow down and not provide OE FP)

That being said, on 95 harnesses there is a fuel pump relay prime wire that normally is on pax side harness. That lead is prob what is being tied into the horn.