Deteriorating Coil Packs?
 

My 2011 Acura TL SH-AWD (non-tech) has a smooth idle, but when I press the accelerator (while in neutral) to increase the RPMs, it feels a little rough. The previous owner had some significant hesitation issues prior to me purchasing the vehicle and it turned out being two bad coil packs. I'm wondering if one or more the the older packs are starting to go as well. I measured the resistance on the packs and they are all within the same range (curiously Acura does not specify what resistance they should be). I replaced the spark plugs when I first bought the car 2 years ago, so they should be fine. Unless they are prematurely fouled due to excessive oil consumption (my car burns about a quart every 2,000 miles). Any ideas? I suppose checking all of the spark plugs would be the first thing to do. Part of me wants to replace the other four coil packs. Don't necessarily want to do that at $68 a pop though.

As a general rule, coil packs either work or they don't. I'd be inclined to look elsewhere for the issue. Have you had the codes read?

Not recently. I'll do that this weekend. Codes can be stored even if there is no CEL?

I'd definitely check out the spark plugs. Get some of the NGK iridiums if needed. You can find them for a reasonable price on Amazon and eBay. Don't buy from the dealer or auto parts stores unless they're running a special.

You could also try running some of that Gumout Tuneup with PEA to clean up the cylinders. With 1qt per 2000 miles I'm betting you're getting some carbon buildup on the exhaust valves and piston heads. If I had an SH-AWD I'd probably be running that stuff every 5 fillups or so. I've seen (via boroscope) some good results on my FWD. The cylinder heads and exhaust valves are literally free of any carbon buildup whatsoever.

On a related topic, the car runs great when the engine is cold, but once it reaches operating temperature, there is a noticeable drop in performance. Does this point to anything?

I've been speaking to an Acura technician online, and the conclusion he came to is tight exhaust valves. Not sure why this would cause sluggish acceleration below 3,000 RPM then all the sudden everything is fine above 3,000 RPM.

I captured some data on the way to work this morning. I'll post some graphs as soon as I get the chance. One thing I found odd is that when sitting at idle, the calculated engine load was over 25%. Is this normal for an idling engine?

The technician I spoke with gave this explanation as to why acceleration greatly improves over 3,000 RPM. It sounded like he was implying the butterfly valve and/or VTEC is engaging sooner than it should, which would explain the drastic change at 3,000 to 3,500 RPM (as opposed to the normal 4,000 and 4,700 RPM). He said when the ECU sees that the RPMs don't match the expected throttle percentage, it engages the butterfly and/or VTEC to compensate.

The mass air flow meter detects air into the motor. The map/ manifold absolute pressure sensor sees what the intake is burning the air at pressure/kpsi and if it sees too much fuel from 02 sensor readings the motor now has to adjust airflow/ open butterfly valve to allow more air in hence tps readings

I think I'll go ahead and check the clearances and adjust as necessary, but I don't expect to feel any noticeable difference.