Hello. I have an 89 gta with the 305tpi motor in it. It is having a problem I can't figure out. When the car sits overnight it is hard to start. Takes 5 or 6 long cranks to start it. But once it starts it will start right up for the most part. it runs good and will take off strong but once I get down the road and it heats up it will hesitate and sputter from a stop but then catches and takes off. The car sat for 12 years before I bought it and has never ran right all the time since I have owned it and tons of new parts and sensors on it. If anyone could give me advice on what they know about this problem. Also rpms jump way up when put in park or neutral form

 

most likely, you need a fuel pump and filter. but first check the fuel pressure. you MIGHT get lucky and only have to change the filter (use a wix brand). check your codes and if you have any fix that first. my car sat in a barn for 18 years when I bought it. I had to get a new tank, sending unit, pump and filter to solve my issues .so I can relate.

 

That was the direction I was headed too so I checked my pressure last night and it spiked at 6 psi and droppd back to zero with engine off. Once I got it started it was about 29psi at idle. Thanks for the advice rusty. I'm going to pull the filter and see if it's clogged but looks like I'll be doing a pump and cleaning the tank this weekend. I'll update what I find