DrPhantum

It's a sad day when I'm posting in the "Repair" forums, rather than "New Owners" or "Modifications..."

Anyway, here's the problem I'm having: Last night, after my Automatic 05 Z Roadster Touring sat on wet grass for 2 days, I started experiencing some very erratic revving when shifting between gears. It doesn't seem to be any two gears specifically, because it happens whether I'm pulling away from a stop sign or speeding up to pass at 60mph.

The car literally *jumps* when it happens... it seems like the car stalls for a a few milliseconds, and then the accellerator is smashed to the floor, and then it repeats a few times. Usually, I let off the gas pedal as soon as it starts happening, so I don't know how long it would do that if I kept constant pressure on the pedal.

I can see the tachometer fluttering between 2k and 3k RPM, too.

Admittedly, the first time it happened, I had it in "automanual" mode and I was accelerating to pass a slow vehicle. I wouldn't say that I was abusing the car in any way... I wasn't even near redline... but I did punch it a little harder than I normally do.

As the RPMs increased, it hit a certain point, and it started fluttering as described above. Now, it happens about 30% of the time the car shifts from one gear to another. Usually, it happens when I'm accelerating at a high rate, as in from a stop sign to highway speed. In the 70% of the time that it doesn't happen, they're usually the "slow shifts" like from 30mph to 45mph on a regular road. Also, during the 70% of the shifts that it doesn't flutter uncontrollably, I can tell that the car isn't as powerful as it used to be. I get this feeling when I'm not shifting as well... the car feels a little sluggish. I may just be paranoid and more aware now, though.

So... give it to me straight... Have a ruined my Z? Does this sound like something the dealership will cover? I've only got 13k miles. Also, I've got an AEM intake and GReddy SP2 exhaust... They can't say that these upgrades CAUSED my problem, can they?

Any help is appreciated. Thank you.

HondaKiller

iTrader: (5)

sounds like a transmission issue to me. I would say change out the fluid, but with 13k miles it is probably something more. I would bring it in figuring you have bumper to bumper.

rcdash

iTrader: (18)

Take it into the dealer and have a service tech drive with you... Something is wrong - don't see how you could've have done anything. Your current mods cannot be proven to affect the tranny so I wouldn't worry about it. Hopefully your dealer will be cool about it.

DrPhantum

Thanks for your help. I really don't see how I could have personally caused any damage, either. I'm sure the "automanual" mode has failsafes built into it to keep damage due to stupidity or ignorance to a minimum. Nothing, though, is foolproof... and sometimes I can be foolish. Like I said, though, I hadn't even reached redline (far from it) when it cut out and started fluttering the first time... it would be a stretch to think that anything was damaged from that.

If it is a tranny issue, then what do you think could have happened, and how long will it take / how expensive will it be to fix? Hopefully, you're both right and my bumper to bumper coverage will help me out.

silverz239

just curious... did you put on aftermarket led's??

DrPhantum

[Edit: Because I have more information to volunteer and I decided my first post sounded pushy... I didn't mean it]

Actually, Yes I did... Only a week or two ago. In fact, it was these lights specifically: http://cgi.ebay.com/ws/eBayISAPI.dll...MEWN:IT&ih=004
Are they contributing to my problem? It's hard to believe, but I guess the difference in resistance in the lights could be changing the voltages/currents that are circulating through the car and messing with my electrical system... but I wouldn't think that it'd have that large of an effect, let alone any effect at all... and I'd think that the car would have voltage/current regulators or something to prevent these kinds of electrical anomalies.

Come to think of it... now that silverz proposes the involvement of the LED tail lights, I think I've only experienced the engine flutter (for want of a better name for it) when I've had the headlights on. I'm sure you're all aware that the tail lights turn on while the headlights are on, but in a "low glow"... maybe something about this "low glow" coming from the LED tail lights is interfering with my car?

*****Important information********
When I installed the LED tail lights, I never hooked up the smaller of the two connectors of the factory harness that comes out of the car. I was told that I didn't have to by another user on these forums. On the stock tail lights, there are two bulbs: stoplight and "headlights on" low-glow light (as I call it). On my aftermarket LEDs, there is a large LED cluster & a single LED in a red ring around it (see this post for info: https://my350z.com/forum/exterior-and-interior/289040-led-taillight-installation-question.html )

As I stated in the post linked above, I have only installed the large LED cluster, because there is no compatible connector on the new tail lights to plug into the smaller socket for the "headlights on" light from the factory harness/lights. All that I'm given for the single LED in the light ring (see auction link above) is two wires coming out of the new tail lights (one black/one white) I've taped off the wires I'm not using, as well as the connector that used to house the "headlights on" bulb on the factory harness.
Does this help at all?
*****Important information********


Do you have any suggestions, silverz? Please check out the post that I linked in the "important information" box I made. I'm very interested in the idea that these LED tail lights are causing the problem... but I'm even more interested in the solution.

Thanks for your intuition.

DrPhantum

UPDATE: I drove the car around yesterday and this morning, and I had no engine trouble whatsoever... I even tried to make it happen by punching the gas and going to high revs. It's the weirdest thing that something like this would happen on such a haphazard schedule. Tomorrow I have to travel about 200mi for a client visit, and I will have many opportunities to cause it to happen.

I just have no idea what conditions have to be met for this problem to present itself.

silverz : Any input?