Need help what would you do?

[Logan541]

I love my 97 Grand Prix BUT it is doing what so many other grand prixs do now, dies for no apparent reason, then in a few days will run fine, sometimes for months last time it ran fine for a year so far replaced, CPS, coils, ICM, IAC, MAF, EGR, wires, plugs. Fuel pressure regulator, Fuel Pump, ran it past you guys on the forum and most say sound like ICM but tried two others even put the old one back.
I love the car but don’t know what to do 3 shops looked at it and no ideas plus on top of this the trans is going. 3 weeks ago I bought a 2014 mustang convertible since I needed to get back and forth to work. I need a second car and am thinking of selling the prix (had so much fun with it though upgrading it etc. Never got it really finished, but am close. I am thinking of selling it and buying a mustang fastback in its place a 2011 ( I have not started looking yet). What would you guys do I mean even if they find the issue its $1,500 for a Trans on top of everything, but its breaking my heart 340,000 miles original owner last car my Dad got to see me with and take rides in with me, the new stang would run about $16,000 loaded. Plus not sure I would trust the grand prix on long trips or as a DD.
It’s N/A 2 door has 2006 leather power seats both sides GTX hood, Bluetooth radio with phone, Painted engine cover stb’s front and rear, police cruiser front sway, only 70,000 miles on the whole new front and rear suspension I put in tie rods, links, struts, power slots with hawk pads. I have but, have not installed torque stars Fbody Calipers, GTX rear caliper and rotors. Should I part it out if I do sell it and put the old stuff back? Should I sell it? What would you guys do? If I sell this and two other cars I have I can probably pay off at least half the stang I have (13k loan on it) then take a loan to buy the other one once its paid off. Bear in mind if someone can give me a definite “this is the problem” I would probably keep it until trans dies completely
Thanks
Logan

[stocker]

I think I'd try to narrow down the problem with help from the guys on here. A shop is going to have trouble narrowing down a random problem like this.

Here are the options I see:

1) If you can't resolve the starting/running issues, get rid of it.

2) If you figure out the engine problem, put a shift kit and trans cooler in for less than $100 and see how long you can go.

3) If the engine, shift kit and cooler, buy you some time you may eventually need a different transmission. At that point in time, review your options. If you decide to replace the transmission, get a used one instead of a rebuild. To buy and have it installed should cost less than half of the $1500 you stated.

If you end up selling, you'll have to decide if parting out is worth your time or if you just want the car gone.

[NebTurboST5]

i dont know if you have tried this but a buddy of mine had a gtp that would randomly die while sitting at a stop light. pulled the engine cover off and it never had an issue after that. we attributed it to static building up under the cover and causing an electrical issue. (hypothetical) i know this sounds pretty far fetched but might be worth a shot. the only other thing i would suggest is bending and moving the wiring harness around while its idling an see if you can find an intermittent short...