Typical gas mileage for 1999 GP?

[Z28]

I get about 21 in town and 28-29 on highway. Is this just a bit low?

Should I clean TB and change plugs or fuel filter?

[coreygnar]

I get about 21 in town and 28-29 on highway. Is this just a bit low?

Should I clean TB and change plugs or fuel filter?

i get 15 in town on my 00 gt

[TheOtherNick]

sounds normal. Cleaning the tb and doing a fuel filter is never a bad idea. Dump some sea foam in the tank and run her empty before you do the fuel filter.

[CTKGP09]

i too have a 99, bone stock i got 20 city and 29 highway, after and intake, dp, plugs, and wires i get about 23 city and 33-35 highway

[Fivefingerdeathpunch]

After just getting mine on monday, I was getting 32 mpg and now that I am back to the city driving its at 21 mpg. I avg 20mpg with work only being 3 miles away and other farting around.

[Z28]

Plugs are a bit tough in the back?

[ZR1Vette09]

yeah. alot of guys talk about unhooking the dogbones and using ratchet straps to rock the engine forward.

[CTKGP09]

i didnt unhook anything when i did mine, the hardest part was removeing the factory wires. they were STUCK

[Fast50dz]

Yall get great mpg. Compaired to me but I have 3.69 gears. I get 14 city and 20-22 hwy if I keep it under 75 lol

[CTKGP09]

ya, my blazer got that haha

[Poil336]

after a night of DD i saw 12.9mpg on my gauge lol. damn granny gears. your gas mileage is normal though. the back plugs aren't that bad, ctkgp09 was right in saying the wires were the toughest part. and those damn plastic clips holding the wires, couldn't get one of those open. if you choose to unhook the dogbones and roll the motor forward, make sure your trans is in neutral so it will actually stay rolled forward. learned that from experience