Running Rough at idle, any new ideas ???

how many miles on her?

have you cleaned the egr circuit/intake manifold?

 

also, do you tend to start the car and shut it down before the warmup cycle has finished?

 

sorry, i was looking at your info thinking 2011. no egr on gen 2.

 

Look at the misfire monitor values? If one cylinder has more misfires swap the ignition coils around.

If you put it in neutral with cold engine running (to get true idle) does it get smoother, worse, or stay the same?

 

What does it feel like when it's "rough and Rocky"?

It shakes all the time? You should try scanning for codes

 

Sounds like the fuel injectors need cleaning.

 

Valve tappet clearances going off is one thing that's hard on idle. Just a thought, though I believe 2nd gen are pretty reliable. And a BEAR to adjust. Maybe just checking the gaps is not that hard?

 

If you aren’t afraid of replacing the fuel filter add a dose of MMO per the bottle then fill her up so you get a mix of E30-E50 gasohol.

If your area doesn’t sell the stuff just mix in a half tank of e85

You might surprise yourself

 

Not sure that one can replace the fuel filter without replacing the whole tank.

Am curious to know more about the half tank of e85 and any results that might produce.

 

Pretty sure it's doable. The attached excerpt from second gen manual shows complete gas tank removal and install, but in the process I believe they show the fuel pump/filter being separated.

 

Here is a guess. To clean the throttle body you had to remove the air cleaner assembly. The junction between these two parts is a clamp, and if you don't re-tighten it there can be un-metered air entering the intake cycle. This is air that has not passed by the MAF. It will run rough until the computer adjusts the mixture. Also, you said you cleaned the MAF. Hopefully you used the specific MAF cleaner. Did you replace the spark plugs with the recommended Nippon Denso brand? As suggested above in post #7, I would investigate the spark plug coil-overs for arcing and the codes for misfires. It is unusual for the ignition system to develop an intermittent, usually only hard failure.

 

E85 is less likely to produce misfire and the misfire if it does occur is less severe in excessively lean or poor compression conditions .

MMO Covers up leaks and increases compression, it also makes the motor sound smoother.

In cases where you will not be repairing the real engine problem the above can allow you to drive it into the ground more pleasurably. Speaking from experience driving a car with a failed engine 60,000 miles.

The reason I put the fuel filter disclaimer is because a very old dirty gas tank will get cleaned out by ethanol and can plug the fuel filter, it’s rare but worth remembering.

 

The g2 seems to have fuel injector issues based on how many posts about them I have seen here.

You have Done all the best choices for a tune up so far so give the fuel injectors a look next.

 

LOOK AT YOUR MISFIRE COUNTS!! Sorry to yell. Ha! I was dealing with a stumbling/running rough issue for 2 months with no CEL and finally plugged techstream in and watched the misfire counts while the car idled. I narrowed the misfiring down to cylinder 3. Swapped the coil pack to cylinder 1 and the misfires switched to that cylinder. Replaced the coil pack for $50 and it is running like new again. If it's misfiring on all cylinders, then you could look for a more general issue like unmetered air/ bad fuel delivery etc. But I personally wasted so much time with my car parked cleaning MAF, throttle body, pulling plugs etc. I should have started with the misfire counts. If you don't have techstream, go ahead and order it. It's an invaluable tool. Here's a link- not the cheapest available. You can totally just buy the cable and download the software online, too.