fist of all does anyone know what an 84 trans am with the lg4 motor (4 barrel carb) gets mileage wise. i just picked one up and gave it a tune up and got about 160 miles on one tank of gas with mixed city/highway. second what mods can be done to gain performance and maybe get better mileage on this thing. would switching out the q-jet carb to a holly or edelbrock help out?? any tips and suggestions greatly appreciated!!!

 

swithching out the q-jet carb if it is working correctly would actually be worse in my opinion just make sure it has a good tune and that the ignition is working good and that should help with gas milage

 

The CCC-Qjet, properly functioning, will get better mileage than any other carburetor. My 85 TA with LG4 averages around 23-24 on my 64 mile round trip to work and back. I averaged better than 27 on a 850 mile trip to Missouri last Summer (AC on the whole way) right after it turned over 200,000. Only mods I've done to it is convert it to electric fan and installed an open element air filter.

'Course she needed a carb rebuild when I got it and the distributor and all components have been replaced. Put the scanner on it now and again to make sure the dwell is set right and all the sensors are happy.

See what you're actually getting mileage wise. Write down your mileage when you fill it up. Repeat at next fill up then subtract the prior mileage from the current mileage and divide by the number of gallons put in. Do this every fill up to get a running average. I check mine almost every time and an unusually low number has, on occasion, been my first indication that something needs a look.

For performance mods that won't sacrifice mileage you can't beat full exhaust.

 

Welcome aboard thirdgen.org.

You're falling for one of the bigger lies out there - factory carbs are no good. As already stated, it's actually the best.

Miles per tank is pretty inaccurate, especially if you're going by the stock fuel gauge. How many gallons did it take to fill it up? That's how you determine fuel economy, not miles per tank.

 

, and full exhaust would help

 

ok ill stick to the stock carb. i got the car and it had been sitting for 4 years. i got the oil changed, replaced spark plugs, wires, cap/rotor, coil. the guy when he put it up for sale emptied the gas tank and put fresh gas in. i tuned it up and filled the tank up completely. it had a quarter tank and i put 11 or so gallons in. i also dumped a thing of sea foam into the tank. got about 160 miles before i had to get gas again. this time i just put $20 in and didnt even get half a tank of gas so im guessing the tank is larger than my 87. so far i think im only going to get maybe 50 miles on this $20 when $20 in my 87 gets me a bit over 100 miles. car does stumble until its warmed up and smokes quite a bit. carb may be reson for stumbling and not running smoothe. choke light not on but who knows. should i just get the carb rebuilt??? i also tried replacing fuel filter and for the life of my i can not get the line to loosen without coming close to stripping the nut. what im seeing now better mileage is what i want!! thanks to eveyone who has welcomed me and gave their opinions!!! any more thoughts and suggestions always welcomed!!