I've heard that they should be changed every 60,000 miles; some people also say "if it ain't broke, don't fix it."

Regardless, mine are least 90,000 miles old and I still get decent mileage. Replacing both will put a small but noticeable dent in your wallet.

Okay, as far as the reference to the gp. We did that math over and over again. I started with a cleared trip monitor and a full tank. I could only put 2 gallons in trust me I tried to get more in since it usually needs more. I was well over 100 miles when I filled up. In reference to the mileage of the bonny it has 112K+.

[QUOTE=YoungGunLs1;1445454]Not saying it didn't happen, but I find this very hard to believe..and I am a guy that was able to get 32.xx mpg in a 1999 Trans Am on a 500+ mile trip with people not believing me, so I know what it is like to have people not believe you when you get amazing mileage..but 50mpg and 42mpg against a strong wind...that I am having a hard time believing..



Yea, I have friends with vettes that say they get close to 30mpg.I believe the trans am. AS far as the GP yea this car has over 175K with the 3.1, by far the least troublesome car I have(and probably the most fun(light as can be).On a normal driving day when it was my daily driver I would still get close to if not above 30mpg even with my lead foot. My dad is getting close to 28mpg just driving around town(lots of stop and go). I am pretty sure that I am not BSing.But I guess everyone can believe what they want.What else can I say....

had a 92 gran prix with the 2.3 quad 4 that did better than 40 in the highway never cared to check to see how mutch better but it did it day in and day out till it tossed the timing chain lol

got a 91 camaro that i just drove fron cheyenne wy to colorado springs co on 3 gallons of gas go figure that one out and it has a 355 700R4 under it but if i lay in to it it sucks it down fast

some cars are just wierd must be a friday car

That'* the first Grand Prix that I've ever heard of having a 4 banger.

I usually get around 16 to 17 mpg. That'* 100% city driving in 30-40 mpg zones with a lot of stop signs and lights.

I don't often drive on the highway but when I do I get 28-30 mpg.