Hello, The car started to run.

Hello,

The car started to run for 20 miles start to buck/ run rough. One time I put in neutral and rev'd the engine and then back into gear and ran fine for next 10 miles. The car started to run rough and buck/buck. I have tested the fuel pump, At first start up it was about 40-42, after ran less than a mile it started run rough, rechecked the fuel pump pressure and was down to 34- 36 psi. When the engine stumbles the pressure guage does move slightly higher pressure. Is this bad or what?

Thanks!

Andy