Ok guys this is my first discussion I’m honestly nervous I’ll make it quick so I have an 04 mustang and I haven’t drove her in forever I finally got the time to fix it so as soon as I start it it drives fine up to 45 mph then when the engine has warmed up it won’t go past 30mph I cut the cats off and I had brownish-rustish water coming out but it turns over and runs any ideas on why it doesn’t let me go past 30 mph after it has heated up?