Mild flat spot, 1500-1800 rpm...
 

New Gryphon 5000 miles ago, 87 Perf custom tune, 2008 SCrew 5.4, Gotts, Mag SISO, stock cats and y-pipe, 100,000 miles.

New plugs, fuel filter, everything else original, throwing no codes. Did the BG clean thing for the injectors, MAF, TB about 10,000 miles ago.

3 things:

Flat spot 15-1800 rpm, right after a shift typically, push a little harder, drives through it.

Smells lean at start-up. Most 50+ yo's will know what I'm talking about:cheesy smile:

Slight knock at hot start, sounds like spark knock.

Other than that runs great, 17-18 mpg average.

thanks!

Randy

Great mileage! I get 15.1-15.5. I don't have your "flat spot". I wonder if the Torque Converter is locking up too soon? Have you monitored that? And if it is, you can adjust the part throttle lock/unlock points in the Custom Options.

I also don't have the spark knock at hot start or the "lean smell". I doubt this is a significant worry, since it is a fairly momentary condition.

Did Bill try to write you a tune to maximize economy?

I really only worry about spark knock under load, or at cruise.

- Jack

Mine's 2wd, and 60%+ of my miles are highway.

Bill wrote me an 87 tow and an 87 performance, happy with both. I'm not getting any pinging underway. I'm about 2000 miles into a Mag SISO, so I'm hearing a lot more than I used to.

I don't run my Gryphon plugged in, so I don't have any numbers. When I searched, CHT came up as a way to monitor lean-ness. Anything else to look for?

Thanks, JnJ!

Randy

Yes, DO use the Gryphon to monitor the CHT. Mine is anywhere between 200-225, depending on temperature and load (I tow). I can't think of anything else other than looking at the plugs themselves for a lean running condition. No pinging underway sounds good to me.

If detonation was causing the PCM to pull timing, I think your gas mileage would be in the toilet.

- Jack

Thanks, Jack!!

Randy