gas Mileage drop after tune up

[Stoner51]

So I haven't done a real tune up in a while. So I decided I would.
I replaced cap and rotor, NGK iridium plugs, ngk wires, air filter, replaced pcv, cleaned EGR ports, cleaned the throttle body, cleaned the IACV. Adjusted the Fast Idle thing all the way down. New thermostat, and rad fan. I think thats it.
Now Im only getting about 330 to a tank before the light comes on. Now I drive 50/50 highway city. And the ac has been on non stop, but this seems a little low.
I am going to check the timing, and check the valves tomorrow.

Is there something I am missing or something I didn't do. no Im not 18 and dont have a heavy foot.

steve

[HelmHoltz]

Timing and Valves is what brought my mileage up, dont forget to re-set the ecu since you cleaned the IACV and TB.

P.S I am old and I have a Heavy Foot!

[Bad_dude]

Iridium plugs are not necessary for this car. The engineers didn't design the car to require iridium so should have saved your money.
What's your idle like? Is it an auto or manual? Tire pressure? I don't think the valve adjustment will differ since before the tune up. It might improve slightly to before the tune up. Timing is important, but I don't think it should effect the difference. How many miles did you get to the tank before the tune up? Check to make sure the throttle plate isn't stuck open after the cleaning. Check the cable if the idle is a little high.
Thanks.

[93redcb7]

stupid question.. was AC not on before the tune up? cause if it wasn't, there is your difference. AC drags a lot on the motor which makes it work harder

[Stoner51]

I realize the car didn't need Iridium plugs, But will they make a decrease in the gas milesage. Tire pressure is 35psi, manual trans.Yes I was using the ac before all this.
idle was set at 650 with IACV off. then put on and it came up to about 850-900.
I was prob getting between 400-440miles per tank
By resetting the ECU I assume You mean pull the fuse for 10 min? If so yes.


What is the normal for our cars.

steve

[Bad_dude]

I realize the car didn't need Iridium plugs, But will they make a decrease in the gas milesage. Tire pressure is 35psi, manual trans.Yes I was using the ac before all this.
idle was set at 650 with IACV off. then put on and it came up to about 850-900.
I was prob getting between 400-440miles per tank
By resetting the ECU I assume You mean pull the fuse for 10 min? If so yes.


What is the normal for our cars.

steve

Your car must be a manual. My car is an auto and I get no more than 320 per tank no matter what. Yes, all proper maintenance is done. The car is in great shape but I had a CB, same car as this one and it was about the same 320 to the tank. Is your idle 850-900 with AC on? If not then it's a little high. It should be about 50 less than that. Did you pull the 7.5A fuse or the 10A one?

[Stoner51]

I pulled the radio back up fuse. and disconnected the neg battery terminal. Yes Its a Manual. and It has 51X,XXX,
It just seemed like it dropped all the sudden, However I drove without the ac and The gas light came on at 390.
so maybe I was over anlayzing, a thing I do a lot

steve

[PR CB7]

i Realize The Car Didn't Need Iridium Plugs, But Will They Make A Decrease In The Gas Milesage. Tire Pressure Is 35psi, manual Trans.yes I Was Using The Ac Before All This.
Idle Was Set At 650 With Iacv Off. Then Put On And It Came Up To About 850-900.
I Was Prob Getting Between 400-440miles Per Tank
By Resetting The Ecu I Assume You Mean Pull The Fuse For 10 Min? If So Yes.


What Is The Normal For Our Cars.

Steve

your Car must be A Manual. My Car Is An Auto And I Get No More Than 320 Per Tank No Matter What. Yes, All Proper Maintenance Is Done. The Car Is In Great Shape But I Had A Cb, Same Car As This One And It Was About The Same 320 To The Tank. Is Your Idle 850-900 With Ac On? If Not Then It's A Little High. It Should Be About 50 Less Than That. Did You Pull The 7.5a Fuse Or The 10a One?

Lmao:d

[wildBill83]

I pulled the radio back up fuse. and disconnected the neg battery terminal. Yes Its a Manual. and It has 51X,XXX,
It just seemed like it dropped all the sudden, However I drove without the ac and The gas light came on at 390.
so maybe I was over anlayzing, a thing I do a lot

steve

Am I reading that right? Over 500,000 miles? WOW!

Also how did you clean all of the items? You may have lodged something further in them clogging them further or blown out the diaphrams ... blah blah blah.. ect ect ect.

[HelmHoltz]

Iridium plugs are not necessary for this car. The engineers didn't design the car to require iridium so should have saved your money.
What's your idle like? Is it an auto or manual? Tire pressure? I don't think the valve adjustment will differ since before the tune up. It might improve slightly to before the tune up. Timing is important, but I don't think it should effect the difference. How many miles did you get to the tank before the tune up? Check to make sure the throttle plate isn't stuck open after the cleaning. Check the cable if the idle is a little high.
Thanks.

Iridium plugs were not invented yet when our cars were engineered. The Iridium plugs for our application should be the right resistance for our electrical system and will last 100K!

[8ball]

Iridium plugs were not invented yet when our cars were engineered. The Iridium plugs for our application should be the right resistance for our electrical system and will last 100K!

when I put iridiums on my auto f22a ages ago, the power went up ever so slightly and the gas mileage went up alot but in about a week the mpg went down and the "power" was still there. It was a waste of money for me because it cause alot of misfiring and such.

[oyajicool]

One of benefits of using iridium plugs is its ability to fight against oil fouling. When I had regular plugs installed, one cylinder on my engine used to be fouled with oil. But I change them to iridium plugs and the fouling of plug is history for now.

[Bad_dude]

One of benefits of using iridium plugs is its ability to fight against oil fouling. When I had regular plugs installed, one cylinder on my engine used to be fouled with oil. But I change them to iridium plugs and the fouling of plug is history for now.

That's good to know.