Am I running lean?

[Denny]

How much of a fuel mileage increase did you notice with these 7557s?

 

[DHMag]

How much of a fuel mileage increase did you notice with these 7557s?

4-5 MPG, both highway and city.

 

[TRSCobra]

switched to 93 octane fuel instead of 87 octane.

Aren't you only supposed to run 93 in these cars? Mine says premium only on the dash.

Of course you'll have detonation with the 87 octane gas.

 

[DHMag]

Aren't you only supposed to run 93 in these cars? Mine says premium only on the dash.

Of course you'll have detonation with the 87 octane gas.

it says "Premium Recommended." that doesnt mean its required. running on 87 octane gives me the same performance as 93 octane. i have chosen to run 93 octane to see if the plugs look any different.

 

[Denny]

I've been running 87 as well since gas hit the $2 mark. I used to run strictly premium but I have not noticed any difference in performance or fuel economy by switching down. I run a stock ECU, and I have a 3.2 MTX with mods.
This brings me to my first question:
I recently re-installed the Extrude Honed and Big Bore Butterfly intake on the car. Before I did however I pulled all the plugs, checked their gaps, only one was off, and ran a compression test. I noticed that about a month ago, when this happened, the plugs all looked normal, one plug did have a bit of whiteness on it, but the rest were brown. I had also done a fuel economy test where I never touched the secondaries, except for one emergency manuever. The tank got over 15mpg, the next time I filled up, I had been running with the intake and seeing secondaries constantly, got 18mpg. Two plugs were checked in the pic earlier, WHITE. Is my intake too much for the stock ECU?
Sensor wise, the thermostat and the O2 sensors have never been changed, I have no idea how old either is. Would replacing either of those, despite no CEL help get better fuel economy? I have rarely seen the 20s with this car since it's been back up and running. I average about 13 to 14mpg, mostly city driving, lots of secondary action.

 

[DHMag]

ok, heres my input. actually, a correct burning plug will be tan.

on the first set of 7557s, i was running a stock ECU. i dont have an EH intake or BBBs. strictly a stock 3.0l DOHC engine. O2 sensors have never been replaced by my lonesome, but the t-stat i have changed. daily, im into high RPMs for extended periods (2nd gear at 40-50MPH for several miles [4000-5000 RPM]). i dont think your intake is the culprit. these engines are the same, but each has their own personality. as far as i can tell, the only thing we have in common, other than running lean, is the 155lph fuel pump. i even had the 155 pump when i did my first dyno. locally, a friend has the same fuel pump and he is running a lot leaner than i am.

perhaps our fuel pressure regluators are at fault. a simple fuel pressure test would answer this. but a fuel pressure tester is one thing i dont have handy to check.

before i switched the plugs, i was getting about 14MPG in the city and about 23MPG on the highway.

I've been running 87 as well since gas hit the $2 mark. I used to run strictly premium but I have not noticed any difference in performance or fuel economy by switching down. I run a stock ECU, and I have a 3.2 MTX with mods.
This brings me to my first question:
I recently re-installed the Extrude Honed and Big Bore Butterfly intake on the car. Before I did however I pulled all the plugs, checked their gaps, only one was off, and ran a compression test. I noticed that about a month ago, when this happened, the plugs all looked normal, one plug did have a bit of whiteness on it, but the rest were brown. I had also done a fuel economy test where I never touched the secondaries, except for one emergency manuever. The tank got over 15mpg, the next time I filled up, I had been running with the intake and seeing secondaries constantly, got 18mpg. Two plugs were checked in the pic earlier, WHITE. Is my intake too much for the stock ECU?
Sensor wise, the thermostat and the O2 sensors have never been changed, I have no idea how old either is. Would replacing either of those, despite no CEL help get better fuel economy? I have rarely seen the 20s with this car since it's been back up and running. I average about 13 to 14mpg, mostly city driving, lots of secondary action.

 

[Denny]

I'll look into a fuel pressure test sometime tomorrow or Tuesday. Seeing as how your MPG was around what I"m getting, I'm thinking those plugs may be worth a shot!

 

[DHMag]

I'll look into a fuel pressure test sometime tomorrow or Tuesday. Seeing as how your MPG was around what I"m getting, I'm thinking those plugs may be worth a shot!

i only put the Bosch Supers in because they were .89 each. after reading thru the paper catalog did i find out they were 2 ranges hotter than stock. but, ive never had any kind of problem with Bosch brand spark plugs.

 

[DHMag]

Denny, have you changed the plugs yet ? im curious to know if it helps.