[opelbits]

Replaced the plugs/cap/rotor a few weeks ago. Plugs had been in for 15-20k miles, so it was time. have a look at the plugs in the pic.

Ended up replacing a couple plug wires as the big rubber boot on #1 (straight boot at plug) tore apart trying to get it off the plug. I did originally use the boot grease when I installed those wires a couple years ago. Also, one of the other wires would not stay securely on the plug as the little black spring clip on the outside of the plug end terminal (but up inside the boot...) had broken. It's been driving okay. As with many things, you do the maintenance work, replace a few things and put some air in your wallet and nothing really seems different

So yesterday I had to go pick up some parts from a guy (71 Mustang front seats, factory white painted aluminum slots for a 77 Mustang Cobra ll, nothing anyone here would have an interest in.....). 210 miles total, 180 from work to his house to my house. It was a beautiful warm June day driving pass corn and bean fields. I figured I'd take my time and enjoy it.

I topped off the tank after leaving work. Immediately got on the highway and started the drive. There and back was pretty much 60 mph average drafting behind semis. And flat except for the last 12 miles home.

Topped off again a half mile from home and I had used 7.5 gallons to go 180 miles. Comes out to be 24 mpg. It's not an exact science, filling up at two different gas stations, so I could be off by a gallon either way. Still puts me in the 22mpg range and much better than my usual 18-19 average on my work commute.

It did good for a 30 year old, 200k, brick.

Old plugs...

 

[opelbits]

Normally in town I get around 15-16. I use D instead of overdrive around town and it seems to get a little better drivability/mpg.
Well, drafting a semi by a few car lengths helps. The lower pressure means less aerodynamic resistance for the old motor to fight.

Since I went east then west on the return, it kind of cancels any head wind or tail

It's 90, actually. In high mileage vehicles I tend to use the cheaper plugs. Everytime I try to use the fancier plugs, there is either no difference in mpg/drivability or longevity of the plug. In fact, my 97 Protégé would give me misfires/stutters if I used anything other than the cheapest Denso plugs.

All of our cars are paid for, I can't imagine having a sub-20 mpg truck payment, insurance and a 25 + gallon tank or dual tanks to fill.
I try to fill up after 150 miles. It 'seems' like less of a hit.

 

[opelbits]

Mine gets 15.8 MPH. So opelbits where is this crossroads demon you made the deal with to get 22 MPG?

Also which plugs did you go with? I was thinking of using the "fancy" ones because I dread doing this task.

No deal with the devil! Don't go over 65 and get three car lengths behind a semi trailer. And no hills, just nice flat highway.

I used the cheap ACDelco plugs same as before. I don't really know the internal condition of the motor, but from the looks of the plugs that came out, it's not significantly burning oil and it seems to be burning fuel fairly cleanly. No leaky injectors and my sensors, egr and doohickies all seem to be working.

 

[opelbits]

Oh, yeah, and my catalytic convertor is a year or two old. From Rockauto.
In town driving would normally get me about 16mpg.