96 Probe 4cyl wont rev past 3500rpms

[1966 dart wagon]

My dads friend came to me with a problem, his daughters car is a 96 probe with the mazda 4cyl engine. The engine blew up last year and a shop replaced it, it has ran great up until about 2-3 months ago and it wont rev past 3500rpms, he changed the fuel filter, i was thinking maybe fpr problem perhaps, or fuel pump. Or maybe the timing belt jumped, cause my daytona use to run otu of steam at 4k the belt was old and stretched and after it was replace it ran great. I'll check those but does anyone know of any "common" problems with these cars, since im not familiar with them at all.

Thanks,
Jack

[Nemesismachine]

I had a civic i timed myself, and I had it 2 teeth off on the cam, making 4 teeth off on the crank. It would bog real bad around 4K.