why does my car slow to a crawl in the heat?


Asked by May 22, 2012 at 01:31 AM about the 2004 Mazda RX-8 4-speed

Question type: Maintenance & Repair

When I am driving in the hot weather, my car slows down and I have to stop and wait for it to cool down.  I do not
see any lights on the dash blink on to say "Hey idiot.. your car is over heating"
Last week I hit a raccoon and broke the plastic parts under the front end and now a ton of dirt, sand and rocks
make their way up under my hood and the car stalled twice which it has never done.
A tester was put on it and the numbers they gave me are  Po 456 and Po 442 and he said something about it
having to do with the emissions but had no idea what.  
Today I took it in to have the oil changed and ask the guy that worked there what he thought.  He told me that it
was probably my catalytic converter, and maybe the sensor got dirt in it because I live on a dirt road... He told
me it would be between 600.00 and 1200.00 to replace it.  I sure could use some help on this.

9 Answers


I think your Radiator is choked from the front grill get it cleaned and check for any results also use a radiator flush if u use regular water for coolant . I think this is because of the radiator because u said alot of sand and dirt got in to the front so thats where the radiator is , And the oxygen sensor has nothing to do with the overheating i know that much if it responses differently u'll lose fuel more quickly because it does not know how much fuel is getting burned in the cylinder Hope This helps

2 of 2 people found this helpful.

Also Check the fan for damage also

1 of 1 people found this helpful.

This makes sense to me... and as far as fuel, I am going through much more , and when I had my tires put on, the mechanic there said he thought that the gas was only being burned once, which of course doesn't make any sense to me because I do not know anything about these things... I had no idea that gas could be burned more than once!?!? I will do a flush tomorrow and see if that takes care of it! Thank you for your quick response!!!


With the plastic parts broken under the motor, what else could be effected? I talked to my insurance company and they said that if this was caused from hitting the raccoon that they will cover the repairs.


the front only has coolers and fans for the ac and the engine "the radiators " so only they wil be damaged


as for the error codes it seems both are concerned with fuel evaporation meaning there is a gas leak somewhere near the tank a very Small one at that check the gas cap if its fully tightened or not

1 of 1 people found this helpful.

If you are burning much more fuel than usual you most likely have an 02 sensor that needs replacing. If the 02 sensor is calling for too much fuel the catalytic converter can get extremely hot. The converter can also get plugged up. This would cause the engine not to be able to breathe. You will notice that engine might idle ok, but when your driving the engine will have no power and possibly run rough. If you suspect the engine is overheating manually check the coolant temp. You can use a hand held scanner, you can get a radiator cap that shows temp or get an immersion type thermometer. If the engine is overheating enough to affect performance you will notice other symptoms as well. The engine will feel warmer, you will loose performance and you will see other engine functions be affected and give you a code.

1 of 1 people found this helpful.
Best Answer Mark helpful

Thank you for the answers! I am sure that because of all the dirt and dust that got everywhere did contribute to some of my problems, after a good flushing and cleaning and new fluid, she runs better, I still have the loss of performance when the outside temp is in the 90's and I have to idle at stops in downtown driving. Country driving is fine. I do need a new gas cap, I believe i do have a small leak there.. I am going to change my oil and filter today and do not have an owners manual, everyone seems to have a different answer add to the amount of oil to put in! Will someone please tell me the correct amount? Also where I could but a new manual? I wish I knew a good mechanic here in Michigan, one who knows what he's doing but doesn't charge an arm and a leg! Thanks guys!

1 of 1 people found this helpful.

I had the same issue with my 04 RX-8 last year, i asked around and all i did was changing the battery, so i advice you to do that and see what happens.

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