2011 Grand Cherokee non-start issue

Hi all,
I am having non-start issues with my Jeep. It started a few months back with not starting after being driven. The engine cranks but just won't catch. Most of the time after 20- 30 minutes it starts right up. It would do that about.once a week but got progressively worse. I had the fuel transfer switch recall for the TIPM done, that lasted about 2 weeks before the issue returned. Had the alternator and starter checked and replaced the original battery. Found a ground strap from the engine block to the chassis was rotted so replaced that. Didn't change anything.
Has any had similar problems and found a solution?
Thanks in advance

 

If it won't start after sitting for a few days, it's most likely something causing a parasitic drain. Those are a giant pain to track down, because they can be caused by nearly every circuit.

 

The weird part is that it does it after being driven. I would drive to the store or somewhere, run in and do whatever, come back out and that's when it won't start. It's left me stranded more then once

 

So it cranks but will not start? Three things are needed. Fuel, spark, and O2.
I'd start by checking fuel pressure. There's generally a Schrader valve near the engine, but not always. It will look like the valve in a tire. You can screw on a pressure gauge. If you don't have one, you can either add one, or disconnect a fuel line and test from that.
Testing the injectors themselves is a bit more difficult, and requires a multimeter. You remove the power plug and measure the impedance across the connections. I'd lean more towards fuel pressure. If an injector goes bad, you get a misfire. It's unlikely enough to stop it from starting would all fail together.
Then check spark. If you don't have an actual spark plug tester, you can still test. Pull the fuel pump relay. Now pull a plug, connect it back to the plug wire, use a piece of wire to ground the threads. Have someone crank the engine and watch to see if it sparks.
I'm assuming there's not a squirrel nesting in your intake. So start with the throttle body. When you step on the throttle, does the butterfly valve open all the way? If not, think throttle position sensor.

 

Odds are that may not be the only ground strap although engine-to-chassis is one of the important ones.

 

Yeah, there's like 4-5 different locations. I tried looking them up but the schematics I found weren't very intuitive on locations