Takes 3 cranks to start after sitting

I have a 1995 Pontiac Firebird with less than 50,000 miles. A couple weeks ago it started slipping into neutral while I was driving and I ended up having the transmission rebuilt. Since then it has had trouble starting. It takes 3 or 4 cranks to get it to start after it’s been sitting for longer than an hour. It’s only when it’s been sitting for a bit. I took it back to Aamco and he said maybe it’s not getting fuel and replaced the fuel filter since it had never been replaced but did not help at all. I’m a bit upset obviously has it had always been starting flawlessly before I had the transmission redone. I unfortunately don’t know enough about cars to know if I’m getting scammed here or not. Is there something obvious that I should be checking before I take it back?

The next time you go to start the engine after it has sat a while, turn the ignition on so the dash lights come on for two seconds, and then turn the ignition off.

Repeat this a half dozen times and then try starting the engine.

If the engine starts right up, it points to a problem with the anti drain-back valve on the fuel pump assembly.

Tester

Well, going to Aamco is a waste of time . They are a transmission shop and not really good at that. A decent independent shop should be able to solve this. They may have left something loose but proving it might be difficult.

AAMCO means All Automatics Must Come Out - you’ve likely already been scammed as a 700R4 transmission generally does not need a rebuild at 50K miles. But that is transmission fluid under the bridge.

There is nothing you can check yourself if you don’t know much about cars. This is likely a coincidence that this happened at the same time as the transmission rebuild. Do @Tester’s trick to see if the fuel pump is going away. It can also mean a fuel injector is leaking.

Stop going to AAMCO and find a good independent mechanic.