TunaPhishSalad

Hey everyone, first time poster, long time viewer. Anyways, I have just purchased my first F-body, a 1997 Quasar Blue Z28 with an A4. Little about the car, my brother owned it before me and bought it originally with 19k miles. It now has 120K miles, and never really has had a tuneup. He has changed the oil and done the intake manifold twice, as well as a new cap + rotor when the leaky water pump took it out. The car has a SES light on, and misses a little bit at idle. Also when your cruising going about 50MPH and step on the gas a little bit, it hesitates. The only mod I think I am going to do to this vehicle is 3.73 gears, as I am going to keep it a daily driver after I sell my 99 GTP. Now to the point.... The car doesn't get the greatest gas mileage as It really hasn't had a tuneup. So, I drop the car off at my mechanic last night with a ton of parts. I am going to have him install another intake manifold as it is leaking again, and a valve cover gasket. I also got a set of TR55's, Plug wires, PCV Valve, Fuel filter, both O2 Sensors, and a B/G Fuel Induction Kit, and some 44k. I have read on the forum that these cars are capable of 25+ MPG highway and that's what I am going for. Is there anything I am missing here in my quest for a great running LT1 that gets decent MPG. I also found out that I have a rear tranny mount that is separated at the bushing, could this be why I have a Clunk when shifting and at WOT. Also, is going with 3.73's the best first mod? (yes I know gas mileage will suffer a wee bit, but have been told by a buddy that this is the best bang for your buck mod).

Guys, any input is appreciated, new to the F-Body.

Thanks

Tom

silver97Z

What gear ratio is in the car now? I would think going to a 3.73 is going to hurt your mileage, more severely if you've got stock 2.73s in it now.

I would suggest a cai kit and exhaust if you're looking for better mileage.

my .02

TobyZ28

Yes the clunk is from the tranny mount bushing being broken.
I personally would do a Seafoam treament the car (search the site for it. lots of info)

seawolf06

Seafoam through the brake vacuum line is a good idea. It would be even better to clean/replace the fuel injectors.

If you're worried about MPG, then you're really gonna hurt yourself by going to 3.73 gears. Not only that, but you will spend $200+ on getting them installed. Get the CAI and a proper cat-back exhaust if you can. Some shorty headers and a high flow cat would be good too while you're working on the exhaust anyway.