I've had this problem, when my car runs for a while, it starts bogging really bad, it's missing bad. I think my exhaust might be clogged, cause a while back i had my cat just went bad on me, the guy thought i hollowed it out at the muffler shop, nothing was inside the cat, i replaced the cat, but i'm thinking that stuff from the cat shot through the exhaust and car is not breathing right, cause i just changed the plugs and wires in september, plus the car was running hot, the gauge would go by the read and i have a 160 thermo in there, plus my temp gauge just went out when i tried to drive it last time. I can't drive it too long, cause the temp was going high i would pullover to let the car sit and cool. Can u guys please help, any suggestions?
thanks

 

Sounds like you should start by checking the coolant level. If its low causing it to overheat then the gauge may not function properly as there would be no fluid touching the sending unit.

 

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