89 buick, runs good for the most part, but down on power, when you step into it, it barely moves, but what is worse after you drive it for a while, and then shut it off, and try to start it again, it act as if choking, it may start, but if it dies, you must wait 20-30 minutes before it will start again. And if it does start it sounds like a john deere tractor. Please help repair shop had it for 5 days, said they fixed it, it ran fine for a week and now back to the same old thing. I will also say, before the shop looked at it, it would start right away, now it has to turnover several times before it will start. Its a six cyclinder with 85,000 on it.
The easiest thing to check for is fuel starvation. When it’s hot, and won’t start, spray Starting Fluid (or, something similar) into the intake tube. If it starts and runs for a few seconds, it has a fuel problem. It could be fuel pressure, or fuel injectors.
When it doesn’t start, check for spark at the spark plugs. You can get the test spark plugs with a clamp, from an auto parts store. If no spark, check the spark producing circuitry.
Hope your car really doesn’t sound like a John Deere.I did pistions and rings on a 1955 two big cylinders 305cid. The guys called it “Johnny Popper”