Buy a gauge or a tester?

[m3recon]

I can buy a new one for 350. But if that doesn't fix it I'm hesitate to make the investment.

[Vtec?lol]

Finding a decent tank is hard as hell.
Try to refinish yours

[m3recon]

Fuel filter is new. I was thinking of fixing the tank issue. So do I buy a new one or refinish an old one. It's an 2.5 motor. I haven't checked all the grounds. Plugs are new. I don't know how old the cat is but it looks like the exhaust might have some issues.

[Vtec?lol]

What engine?
Connection on the fuel pump tight/clean?
Cat old?
fouling plugs?
Rotting ground wire?

Usually this would be signs of a clogging fuel filter. After letting the car sit for a while or cool down, the sediment in the filter is allowed to settle thus giving you plenty fuel pressure until it slowly clogs back up. and if this is the case, your tank might be rotting.

[m3recon]

Pump looks brand new but I have a spare. CPS tested within limits. It seems to be heat related. After the cars cools down it starts right up.

[delfin]

Check your CPS and fuel pump first

[Conki]

I'm looking to install either a fuel pressure gauge or buy a tester. What is the best option. I took my e30 to a mechanic because it likes to die on the freeway! Guess what my car didn't do while he had it.... That's right I'm back to fixing it myself! So I'm starting with fuel....

You can test fuel delivery with a watch and a cup, but troubleshooting an intermittent problem is a PITA.

[m3recon]

I'm looking to install either a fuel pressure gauge or buy a tester. What is the best option. I took my e30 to a mechanic because it likes to die on the freeway! Guess what my car didn't do while he had it.... That's right I'm back to fixing it myself! So I'm starting with fuel....