So my 2011 TL-SH AWD doesn't accelerate as smoothly or rapidly as it should and it is extremely irritating. I don't know if it is misfiring or if something is going on with the transmission. If I'm above 3,000 RPM, it pulls pretty strong, but there are times when it hesitates. It's like the ECU is confused as to whether I want to accelerate quickly or gradually. For example, I can be in sport mode at a dead stop, light turns green, then I give it pretty much full throttle and it doesn't take off as it should. It hesitates until I reach about 3500 RPM, then starts to take off. But when it shifts gears, it hesitates again. I'm about to sell this frikin car. I don't how to explain it, but it's like someone is applying the e-brake then disengaging it while I'm accelerating.

 

Off the line you need to modulate throttle so that traction control doesn't steal your power. I don't think SH-AWD can transfer power to the rear wheels if the front wheels spin so the computer will cut throttle to avoid that.

If you gradually apply the gas, it allows the car can transfer the weight and torque to the rear wheels so you can put all the power down.

The fastest I've ever launched my TL was for an autocross run where the starter said "Go, no wait, alright" while I was doing a brake stand. The slight roll due to the hesitation allowed the system to prepare and the car just rocketed forward when I fully released the brakes.

 

Mossman. My car does the same thing under moderate acceleration from a stop. Especially when cold.

I think it is the transmission programming. I think they are programmed to maximize fuel economy and be in the highest gear possible in any situation. May also be related to the torque converter. Have you had it to the dealer for a PCM firmware update?

Might try that and a transmission fluid change. The fluid change may be included if your car falls under the torque converter TSBs.

 

There was a story a long time ago about improperly installed spark plugs causing misfires that aren't registered with the ECU, so no MIL light on the dash. But the software the dealers have was able to diagnose that. What happened is that some of the spark plugs where literally thrown in the cylinders during installation and bent their tips. If no dealer available or you want to safe your money if out of warranty, it may be worth pulling out the plugs and visually inspecting the tips.

 

I replaced the spark plugs when I purchased the vehicle last year, so I don't think that is it. Although I did replace them with Denso when I believe it called for NGK, or vice versa. But I had this issue prior, so I don't think that is it. The previous owner had to have two of the coil packs replaced because he was getting really bad misfiring, so perhaps one of more of the others are on their way out as well. I did a simply resistance measurement on each, and they were all within the same range (curiously the service manual doesn't specify the actual range), but that doesn't mean they are behaving properly when thousands of volts are applied. I'm not sure if it's related, but I get the same behavior when my stereo system is playing loudly (500W amplifier, subwoofer). Makes me wonder if the alternator is not strong enough to provide the proper current for everything and it is affecting engine performance. I'll be replacing the alternator with a high current model this week, so we'll see what happens. I doubt there will be any difference though.

 

Yes, the firmware has been updated. I'll be doing another fluid change in the next few weeks.

 

Does it behave the same with traction control off? I've felt the same on mine, and it's a stick.