Im so pissed right now, last tank I got 11mpg...I used to get 17mpg all day long. Anyway, after that tank I decided I was going to baby my car, I shifted below 2500 98% of the time, went WOT 3 times...and got 9mpg...whats the deal here? I scanned it and one o2 is at like 815 when I go WOT and the other is 925 or so...is the one at 815 reading that and adding more fuel to that side and getting ride of my gas or what? I just don't get it on what could happen all of the a sudden, aside from the o2 reading being a little low, no codes or anything.

 

fuel filter??? when was the last time you had it changed out?

hopefully you don't have my luck....with my car it never seems to that easy

 

sucks too with gas prices being so freakin' high. I feel your pain

 

I would check/replace the Fuel filter, air filter, plugs, wires. Then see how it does after that.

Tyler

 

air filter is new, plugs are pretty new, wires aren't very old. Fuel filter I have no idea....here is my question before I change that. If its clogged and letting less gas through...wouldn';t i get better gas mileage or the car run like ***? Im not questioning it, I just don't understand it and would like some info

The car feels great btw.

 

Maybe o2 sensors? Is the car throwing any codes? Maybe running too cold, it can do that with the lower temp thermostat.

 

no codes with datamaster, the only thing that looks slightly wrong is one o2 reads 100 less than the other at WOT 800/900. Too cold...hmmm, I dunno, maybe, but I don't think so, I have had the 160* in for a while.

 

What temp does the scanner say the ECM is showing? If the temp sensor is bad and the ECM thinks the engine is still cool, it will richen the mixture up.

2 other things you want to check right away. See if the oil smells like fuel. If so you probably have a dead cylinder. The other thing is either use a themometer on the ex manifold or pull one plug wire at a time until you pull one that has no effect on the way the engine runs. I suspect you have a dead hole.

BTW if your oil smells like fuel don't use the car until you find the problem. Cylinder wash down or "souping" is bad for the cylinder walls.

Dave

 

what do o2s show while cruising?

 

Temp shows 164-171 on datamaster. I have the 160* and teh fans on high most of the time.

I will try smelling the oil, but to be honest I don't think I have a dead cylinder. The car pulls pretty well. The last tank I got 11mpg I raced and beat an LS1 WS6 and actually pulled past him in 3rd, beat a 400fwhp eclipse from a roll...so the car appears to be running fairly decent, although I think it is kinda rich...obviously.

 

going from like 100-800 and all over.

One thing is that when the car is idling sometimes the readings move around like 700-900...thats pretty nuts for idle isn't it?

 

mine does the same thing. Im goin to try replacing the 02's since Ive never replaced them. one or both could easily be a little off, throwin off the mixture and makin it run rich. or you could have an inj. thats not working properly. either rich or lean. but that would prolly throw a code. do you have a fuel meter? if so, hook it up and make sure the press. doesnt drop off by itself when you key up the ign.w/o the eng. running. it should hold press. for a while.
chris