Is there any way to change the shift point on my '03 Frontier S/C? Even under light throttle pressure, my truck will not shift from first to second until
3000 RPM and 4000 RPM at moderate pressure. This seems to be pretty standard after driving another one like it and getting the same result. My wife's Xterra shifts at 2000 and I feel like I am wasting a lot of gas. Any experiences/suggestions?
It's done electronically, yes it can be done if you can find someone who knows how to reprogram the trans computer. I have no idea if the EFI computer and the trans computer are one in the same now or if they have a separate computer like the older cars did. The Xterra trans computer might be "the same" as far as swapping them out? Again no idea on that one either. Nissan does tend to make their highpo cars with automatics shift fairly late for performance reasons, might have something to do with making it live as well? I'm sure the s/c has a different map as far as line pressure etc as well to keep it from burning up. You might be able to fudge it with a throttle switch adjustment, but that affects the EFI and the line pressure etc as well.
IMHO short shifting doesn't always "save gas", you end up with more throttle opening at lower revs to keep the same accelleration rate. Hate to sound like this but a s/c automatic truck isn't a good choice if fuel milage is a concern!
Oh I understnad completely. It's just that the way I drive 90% of the time I feel like there's an extra 1000 RPM where I do not need the power because I'm not on the throttle much at all. My Charger has a manual-shift automatic tranny so I can shift whenever I want of course. I have a prosthetic leg so although I can work a clucth, I am not very good/quick with it so it is not a convenient/safe option for me. The Xterra shift program seems to work better. It shifts pretty early at low throttle pressure and shifts higher as expected with increasing throttle pressure. I just thought my truck should/could behave the same way.
My Axxess was shifting late/hard after I installed new injectors. It seems that the cable that goes from the throttle body to the transmission was a little out of adjustment on my re install. It only took a little to get it to a smoother and lower shift point.
Not sure if your Frontier is the same but its worth a look.
For the same potential fuel savings you might get from an earlier shift point, keep your tire pressures set as per factory all around, check every week. As little as 3PSI low difference in tire pressure leads to increased rolling resistance and thus less fuel economy.
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