Doctor OldsI Need A Remedy For What's Ailing Me.Premium,VIP
1970 442 W30
It sounds like you need to take it back to the last person to work on it as they have made it worse, not better. If they are in over their heads then they should return your money wasted with them and you should not try to have friends work on your car if they don't know how to properly diagnose and fix what you own.
Or eat the money you spent, never take it to the last person to touch the car who actually made it worse. Now go to the local Dealer to request a diagnostic and estimate for repair. Don't ask for a Tune up, instead tell them exactly what symptoms you have before and after a friend worked on it. Saying you need a tune up doesn't tell the technician to look drivability issue, it tells them to replace the spark plugs as required for the manufacturer's maintenance schedule, not look for damaged or defective components and stored trouble codes. Of course there will be a diagnostic fee you will have to pay if you don't have the repairs performed at the Dealer after they check the vehicle out and give you a diagnosis...
Car care advice - What Does Drivability Mean?
TROUBLESHOOTING DRIVABILITY PROBLEMS
You will find out it would be cheaper in the long run to just go to the Dealer yourself and tell them what exact symptoms you are experiencing as a tune up is just replacing the plugs since the computer controls/adjusts everything else.
Whats the point of owning a supercar if you cant scare yourself stupid from time to time?