gas mileage - replaced just about everything.

[onspeed]

My car use to get ~240 miles to a tank (when the gauge shows E, about 1.5 gallons left) which is about 17.7 MPG. This i thought was rather low, considering people here say they usually get ~20 in the city. A few weeks ago, my second coil died, so i replaced all three, as well as my spark plugs, and plug wires. That following tank of gas only went 210 miles.. or 15.5 MPG. I figured maybe when i was driving with a bad coil, O2's might have gotten fouled, so i changed those too. Next tank of gas went about the same distance, 210 miles. Fuel/air filters are good, plugs, wires, o2's, cat, coils, fpr are new as well. car was seafoam'ed about 5k ago. oil is good. tires are inflated properly. car runs and idles good... i'm out of things to replace. suggestions?

5 speed, 98 camaro.

[Jaysan]

Re: gas mileage - replaced just about everything.

fuel filter and if you have extra weight your carrying get rid of it

[venom3300]

Re: gas mileage - replaced just about everything.

i have the same problem, around 15.5-16 mpg city.... for me its a combination of school being 2.5 miles away (never holding a speed) and my foot. i get 18-20 mpg city when out of school cuz i go maore than 2.5 miles and hold speed more... so ya might be nothing

[onspeed]

Re: gas mileage - replaced just about everything.

filter is good. car is clean, no extra weight.

i've been driving the same route, just after that coil died, i get 2 less MPG after replacing parts.

[venom3300]

Re: gas mileage - replaced just about everything.

TB need cleaning? carbon build up? how many miles u got?

[Cammy98]

Re: gas mileage - replaced just about everything.

Does the temperature effect gas consumption while the car is running. Doesn't the car consume more fuel due to cold air?

[TheGr8Schlotzky]

Re: gas mileage - replaced just about everything.

My EGR was leaking..sealed it up and my gas mileage went up 4mpg city. Might as well replace PCV, it's like 2 bucks.

[bwkmaro]

Re: gas mileage - replaced just about everything.

what kind or coils did u put on if there not msd or acdelco thats ur prob and as for plugs if ur not useing idridiums thatll rob even more. take it from expirience.....

[bwkmaro]

Re: gas mileage - replaced just about everything.

oh and as for the O2s dont run bosch in 10000 miles they be bad again :( i dont like bosch stuff anymore i ran it all for a while and things just went down hill

[The Banks]

Re: gas mileage - replaced just about everything.

if ur not useing idridiums thatll rob even more. take it from expirience.....

Thats not necessarily true. Just because those plugs cost $6-$8 doesn't mean its better than a $2 copper core. The extra cost isn't worth the negligible gains for a lower resistance plug. I don't know about you, but I'd rather disregard the sales pitch that iridium plugs last for 100,000 miles (which is the only real reason to rationalize buying them) and put in some good TR55's every year or so.

[onspeed]

Re: gas mileage - replaced just about everything.

TB was cleaned not too long ago, i've only had the car for about a year... drove roughly 10k since. odo reads 99000 right now. coils were replaced with OEM replacement ones from autozone. i highly doubt just because i'm not running 40-50$ "high performance" coils that my MPG is so low. no SES.. faulty EGR would trigger one right?

[ne0hisda0ne]

Re: gas mileage - replaced just about everything.

faulty EGR would trigger one right?

a faulty maybe, but not all the time...and a leak... I don't think it'd catch that at all...I could be wrong though...

[bwkmaro]

Re: gas mileage - replaced just about everything.

msd coils put out less voltage than the stock acdelco ones and are cheaper cause they are not as good. and as for iridium plugs(o.e.m plugs btw) they lasted 100,000 they will do it again. and its not always about the hp you notice sometimes its just the fact it runs smoother IMO but our v6 camaros put 200 hp out brand new to the crank becuase of the fact that they r factory tuned the ignition and intake system are way overkill for our cars. and when u put in replacement parts that are not as good as what u get from the factory you will not get the factory hp end of story

[onspeed]

Re: gas mileage - replaced just about everything.

So you're saying that because i don't have expensive coils and spark plugs, my car is getting about 5MPG less than normal?

[bwkmaro]

Re: gas mileage - replaced just about everything.

yea accually, yes it really sucks but i had the same prob i had copper spark plugs in for 10000 miles and one of my friends pionted out the iridiums and how they were o.e.m so i gave it a shot and in the 40$ i spent on the plugs ive already saved that in the 3 months ive been driving in gas money. im not trying to knock anyone or what u did im just talking from experience and on true facts. just for sum numbers to try out b4 i did the tune up id put 0-60 in 7.2 secs all day long and 0-100 in 19 secs now i pull 0-60 in 6.5 and 0-100 in 17 secs :rock: