RCTrucker7

Good morning everyone.
About two months ago, my 2005 GT (Manual Trans) would idle kind of weirdly when I would stop. The Tach wouldn’t do any noticeable movement, but I could feel the engine really doing some odd running. It almost was like it was getting ready to stall out, but then it would catch itself. The only other symptom it was having was when I would be traveling at hi-way speeds, and I would accelerate to pass, or just to have a little momentary fun, it seemed like I had no power available at all. I would consistently have to drop to 4th, sometimes even 3rd, to get enough power to do any hi-way accelerating.

This went on for about 2 weeks, until finally my Check Engine light came on. I took it in, and the end result was that two spark plugs had "gone bad" and had been replaced, along with a bad ignition coil. This was about 3-4 weeks ago.

Now, as of about 2-3 days ago, I'm noticing the same thing happening, as far as weird idling at stops. Its doing (although not always, and not as often as before) the same thing that it was doing before. But now, I'm seeing the Tach definitely doing some moving. At a dead stop, my usual idle is 750RPM. Now I'm seeing it mainly still at 750, but frequently slowly lowering down to 500, and on more than several occasions, nosedive to 250, almost stalling the car out, but then shoot up to 1,000 then rest back down to 750 again. The other thing I've noticed with my idle is that when I'm coming up on a red light, say at about 500ft or so out, I'll put it in neutral and just coast up to a stop. What I'm seeing now when I do that, is that my RPM's will sometimes be up at 1,300 - 1,500 and stay above 1,000 until the light turns green again.

I've "tested" the hi-way acceleration issue, and I don't think I can trust myself for results, because sometimes it seems that it's obviously happening again, other times it seems fine, where as the first time, the hi-way acceleration problem was always consistent.

So, should I be worried/concerned? Keep going until I get a Check Engine light again (assuming I'll get one at all), or be pro-active and take it in to the Dealer?

As always, thanks for your help and input.

__________________
Go Slow or Go Fast. I really don't care. Just GO!

Year & Model:
2005 GT 5 Spd

Dyno Numbers:
Zero. Dynosaurs are extinct.

Quarter Mile Time:
It's 25% of the time it takes me to go a full mile.

Mods:
Installed:
SLP LoudMouths
Steeda Complete C.A.I. Kit
Motive 4.10 Gears
SCT X-Cal2 Tune (By American Muscle)
Sequential Taillights

Next:
Hurst Short Throw Shift Kit