stroked383HSR

iTrader: (12)

I used to get 28 or so per gallon on the interstate but now its hard for me to get 23 miles per gallon.

I really cant remember anything i have changed except for did plugs, wires, fuel filter...a few 1000's miles ago. I didnt remove the egr and stuff under the drivers front fender.....surely that didnt effect the gas that much or did it?

Sales2@Texas-speed

iTrader: (5)

How many miles on your current o2 sensors? What air filter are you running (and is it clean)?

99Bluz28

iTrader: (35)

How about your tire presure and/or different size/brand tires, has any of this changed?
How about the airfilter, and check the mafs.

stroked383HSR

iTrader: (12)

O2's? i dont know how many miles on them...I bought the car with 135000ish and I now have 197000ish and I havent changed the O2's or anything, I figured when they go bad the SES light would come on?

K/N filter and I keep it clean all the time along with the MAF.....tire pressure has stayed the same i always check that cause i do so much driving with my job.

stroked383HSR

iTrader: (12)

whoops and I meant to say ...I did! remove the egr and stuff under the front drivers fender and removed my air tubes off the exhaust manifolds.

I am gonna get my headers installed soon along with a dyno tune

reeperz28

iTrader: (1)

Go ahead and check all four of your o2 sensors with that kind of mileage curious if your catalytic converters are plugged up.

stroked383HSR

iTrader: (12)

how do i check that kind of stuff?

joecar

With that many miles you need to replace your O2 sensors.

Check if you can feel exhaust pulses with your hand behind the tips, if you can then your cats are not clogged... if your cats were clogged you would see poor acceleration.

stroked383HSR

iTrader: (12)

seriously? wouldnt the SES light come on if they were going bad?
stupid question but how many O2's do I have? 2? how much do they cost?

joecar

No, they're not "bad", they're still within the PCM's pass criterion even tho their response time has slowed down (they still allow the PCM to trim fuel, but because they have slowed down the PCM ends up adding a little too much fuel).

You have 2 front O2 sensors (used for closed loop trimming).

You have 2 rear O2 sensors (used for testing catalyst efficiency), you can leave these alone.


They something like $50 each or so.

stroked383HSR

iTrader: (12)

and that could be the cause of killing 5mpg's or more ?

4? damn!
but once i put my headers on I will only be using 2? correct? I think when I had "frost" mail order tune, I cant remember if he turned off my rears or not.

but anyways, once i do the headers and ORY + tune, will i get some of my MPG back?

stroked383HSR

iTrader: (12)

hmmm? well I cranked up first thing this morning and cold startup I figured the pulses would be pretty hard when checking. Ive got a Borla with NO plate and the exhaust pulses were not as hard as I thought they would be. I could feel them but almost was just a steady flow if that coming out. not hard though

Sales2@Texas-speed

iTrader: (5)

Yes, your O2 sensors need replaced BEFORE the SES light comes on! They have something like a 50-60K mile service period!

joecar

+1 what Matt said.

Go for a 30 minute drive and then check the exhaust pulses at the tips

(if cats are clogged you will see poor acceleration).

jimmyblue

iTrader: (11)

Deleting EGR does cost you light-throttle fuel economy.
How much of the MPG loss came after the 3.73s?

stroked383HSR

iTrader: (12)

car was purchased with the 3,73's...so i was getting the 28 or so with the same gears.

stroked383HSR

iTrader: (12)

I checked the feeling of the exhaust after a 300 mile trip home and I really cant feel any pulses....its just hot as all hell!

I used a hand towel infront of the tips to see if the pulses moved it and NOPE.....towel stayed steady.

beyonddisturbed

iTrader: (5)

my gas mileage was dipping until I replaced my fuel filter. worth a check if you havent done it in a while.