1990 Monty. 186,000 miles.

Ok, so here we go. I am still having the hard start issue. I can crank the engine once and it would start fine; go to the store and back out to my Monty and have to crank it 10 times. Happens at anytime during the day and is nothing consistent. A new issue is that that just started in the past month.....sometimes if I'm accelerating onto a freeway or to get into traffic, the engine hits 4,000rpm and just stops there. Other times it doesn't. Almost like a rev limiter kicks in. I have no engine codes and have replaced everything that would possibly cause the hard start issue. ECU, IAC, MAF, fuel pump, fuel filter. It also has a new distributor, wires, plugs ignition coil. I have taken it to three repair shops and they can't find the reason. Also, after I replaced the IAC it does have a high idle. The idle will fluctuate from 1,000rpm-2,000rpm, so I'm thinking about putting the old IAC back in to see what happens. It doesn't stall anymore while I am driving, like it used to, so that's a good thing. I tested my fuel mileage and I'm getting between 16-17 mpg. Am I missing anything?

Thanks!!!!