GT Red Line shifts and the Auto Tranny

[chaase]

I have a question for you automatic owners. I have an '04 GT with the Auto stick and when the car shifts at the red line (about 6k). When it hits the next gear (at about 4k) it seems like I don't have any real power. If I shift a little earlier I don't notice it. Is that normal for the car, maybe due to the gearing or something. I am going in for an oil change soon and was wondering if it is something I should have them look at. I hear about the issues of missing around here, is it this problem?

Thanks,
Chris

[2step]

You may get some other opinions on this but here's mine.
These 2.4, PT engines make the most horse power and torque between 4000 and 5000rpm in stock or near stock form. (numbers rounded) After 5000rpm the power starts to drop off quickly. By holding the gear all the way to 6000, you're getting out of the sweet spot where the most power is made.
If you do a search for some dyno test charts or pay for your own dyno, you can learn a lot by studying when the power kicks in. Also note how much the drop is in RPM upon each gear change. Blend these two observations to max your production of power. Try to shift before the power drops off and drop down to where the power is already gotten high.
Another answer to the other part of your question is, yes there can be some loss of power due to plugs and wires. Wider gaps tend to cause missing at high boost. Gapping the plugs down to .042 or even .040 and replacing older, worn wires with high performance wires seems to help. Check around the older posts here and you will find lots of info on cooler air, better grounds, intakes, more boost, etc. Everyone has a little different set-up then the next person but we're all learning from each other.

[ATLPTGT]

Well said 2step.[^]

[SteelBlueGT]

I think there is actually 3 steps to the missing problem at high rpm's. Plug and plug gaps, wires, and PCM. I have gotten very smooth performance out of Iridium plugs gaped wide at the factory and MOPAR performance plug wires. No need to go the PCM route but I should just to be on the safe side. By product is more consistent highway mileage in the 24 to 25 mpg range at 80 mph.

[SuGamer]

Take out the plugs, gap them at .040, and replace the crappy wires with Crane Firewires or Magnecor wires (both have lower resistance per foot) than Mopar wires. Also, in autostick mode, do NOT let the computer shift the car by itself. It only shifts to avoid any damage, not for power. By that time, you hit the power peak and are headed back down. Shift it yourself when it gets to 5000 rpm. The max HP is acheived at 5100 rpm, so if you shift it at 5000 rpm, the slight delay will ensure it shifts at 5100 rpm. Thus, your power after the shift will not feel like you lost power, but rather continued to gain it.