2 days before my car started 'acting' weird, the "Overheat Exhaust Sys" idiot light came on for a few hours but went off again and all was right in the world. THEN a couple of days later when I was starting my car, it went to hell, ran weird. Like it was on 1 rotor. I have replaced; plugs, wires, coils, distributor and related parts, even the oil and added a quart of MMO. Still, it runs like hell and once again the exhaust overheat light is on. I even checked my timing, right on the mark, both of them. It idles a little fast, but does all of this have ANYTHING to do with the exhaust (catalyst) overheating? I am about to run out a buy a new engine but before I do, I need to know if my exhaust could cause a compression test to be off and the engine to run as bad as itis. I have no power. Please help, PM me or if you want to email me, Ill pass my email address if requested. -Scott

 

That particular idiot light is linked to a temp. sensor in the floor pan above where the OEM main cat should be.

if your cat's are either a) OEM, or b) questionable then that's probably the issue.

It would easily cause all of the above symptoms.

try disconnecting the exhaust at the manifold, putting on ear plugs and starting the car, if better then your cats are shot, if not, then it's motor.

 

I'll give it a try, Im just freaking out as my my Rx 7 is everything to me, well... except for my wife and kids, but I cant believe its running so badly. Thanks again!

 

no problem. if the cat(s) are bad, I'd suggest the RX7.com Bonez presilencer + cat if you're going to retain the stock manifold. I have it and LOVE it.

 

cool.... Ill check into that.

 

Most likely it is the main cat. Take it off and shine a light through it. Chances are it is on it's last leg. While it's out, drill some holes through the catalyst, reinstall and see if that helps. Tome to start looking for a replacement.