05TouringRX8

Okay, first some history here. Car got flooded badly a couple of months ago by a family member that didn't know any better. It took several hours of some pretty harsh trying to get the car to restart. Ran really rough for a little while after getting it started and it even bogged down and died (it's a AT) at the first couple of stop lights I drove up to but eventually smoothed out. About the time it smoothed out, the CEL came on and it was throwing a code for a "random cylinder misfire". Cleared the code and was fine for a couple of weeks. Now, over the past couple of weeks, the CEL has been coming on and going off randomly but wasn't on when I went to have it checked, so they wouldn't even try to scan it for me.

Okay, I told all of that to ask about this: the last couple of times my daughter has come home in the car, as she idles into the garage, I hear a sound that resembles the idling of a diesel train engine or even possibly one of the pod-racers on Star Wars I, if you recall that movie. I haven't driven the car but it is definitely coming from the engine and sounds like it would be vibrating the car terribly. She hears it as well but says the car doesn't feel or drive any differently than usual. Of course, she's female and she's only 16 (sorry, no offense to any 16 year old female mechanics), so I guess I need to go drive the car myself to tell for sure.

Anyway, the sound has a low tone to it but is very noticeable as if the engine is out of balance or something, almost. It's getting her from A to B and the CEL hasn't come on for a couple of days - but something is obviously wrong. Just not sure where to start. Any ideas?

Jon316G

iTrader: (1)

The random misfires were likely due to contaminated spark plugs from trying to recover from the flood.
If you haven't changed out the plugs in awhile, you might want to consider it.

Also, with poor ignition (and constant attempts to start a flooded engine) you dumped a good amount of fuel into the exhaust and this will affect the cats longevity... just keep that in mind.

05TouringRX8

Okay, some updated information. I went out to ride it around and the CEL was back on. So, I took it to the auto parts store and it is giving code P2096 - system too lean. I just searched this code on the forum and, while it seems there are lots of possible causes, the common denominator with 2 of the threads I found is the CAT. 2 other posters claimed to get this code when either removing their CAT or replacing it with a high flow CAT. Is my issue likely the CAT as related to the flood recovery or a sensor maybe or a leak somewhere, given the history above? Is there a way to just test the CAT?

The vibration and noise is nowhere near as bad in the car as it sounded to me outside the car. It's actually not bad at all with the car in park, it's more noticeable at idle with the car in gear (AT). It still runs strong but seems like it still may be missing or stammering slightly at idle. When in park and slowly pressing the accelerator pedal, there is a noticeable tick that gets faster the higher the rpm goes. Is that a leak somewhere possibly?

I don't want to chase this issue all over the motor and exhaust system. Would I be better off taking the car to a dealer and have them check the usual things and get it back in good running order? Or am I likely expecting too much from that experience?

05TouringRX8

Trying to figure out where to start here, on my own, if at all. I've been searching and reading the forum. I think it makes sense to buy and install some new plugs for sure. I found a plug DIY and am comfortable that I can handle it. But I see some discussion about changing coils as well. This appears to be more expensive so I don't want to do it if not needed. How can you tell if coils need replacing? And is there a DIY somewhere for that - I can't seem to find one but am probably just not searching right.

I guess I still need the CAT checked too, right? I mean, I doubt changing the plugs is going to fix the overlean code, would it? So, how does one check a CAT? Does it take a muffler shop to do that?

Jon316G

iTrader: (1)

The common component to fail in the ignition coil is the ignitor.
Unfortunately... there is no simple way to check it with a meter alone.

Sometimes its as simple as removing the cat pipe and looking inside at the honey-comb material to see if its broken apart.
And/Or you'll find the material falling out of the pipe when you stand it upright.

The cat is covered under warranty for 8yr/80K miles, so if the cat is bad, take it to the dealer to get it replaced.