well i have installed hood vents and put in a cooler thermostat but my 2000 xj every once in reach 210 degrees and when i fire it up wil have the worst misfire in the world but it only does it when it reaches 210 im running outta ideas on what to do

 

Research heat soak issue in cylinder 3, 2000 jeep cherokee. There is a TSB from Chrysler on it. Injector 3 needs some extra insulation around it.

 

i have also done that to my whole fuel rail with heat wrap and it is still there

 

when did it start after you installed the vents

 

Do a wet and dry compression test and let us know the results. Do you have a CEL? Whats the codes? It could be a lot of things

 

it has done it ever since i rebuilt the motor last year it comes up as a cylinder one misfire

 

Has it overheated since you rebuilt it?

 

well it was doing it before this i believe, but last year i wrecked it around the block from my house and when i pryed it off the pole it was on i hurried up and drove it home then the surpentine belt pulley broke and it overheated for a second.

 

as a matter of fact it was doing it before it over heated that is why it has the 180 thermostat

 

I would recomend you check compression too. I had a random misfire on cyl 2, would run a little rough at idle but plenty of power. #2 was 90 psi rest were 125-130, leak test showed major leakage so I tore it down and found that piston and cylinder wall damaged.

 

well i just rebuilt the motor and bored it 30 over im thinking worse case scenario the head gasket maybe

 

Well if you do the compression test that could rule out a cracked head too.