I'm curious, will haveing a new computer help in any other ways, like better mileage, or performance?

 

Only if there were problems with the original. They will likely have the exact same programming.....

 

I have the 5.9 and have another new computer question. Back when I bought this truck '95 in 1996, the guy said something about it having a performance chip? Is there such a thing and do I need to reinstall it now?

 

That'd be aftermarket like SuperChips or similar. I honestly have no idea how much they can help on these engines, but typically gains are VERY modest with speed density. But no, you don't need to worry about it or reinstall it.

 

95 is OBDI, so, not flash programmable. So, not tuners available for it. The 'performance chips' that I see on EBay, etc, are just resistors connected in-line with IAT sensor, trying to fool the computer into thinking the intake air is colder than it really is, so it injects more fuel. They make dramatic claims, but, it's all lies. I am truly amazed that those things are still even legal to sell. Once the truck goes into closed loop, those chips do absolutely nothing, as the O2 sensor will prompt the computer to correct fueling.

 

I 'd like to see real world dyno results for the JET modules. This is what they are calming but looks like crap to me.
https://jetchip.com/wp-content/uploa....9L_Module.pdf