I have a question.. I have a 2004 Acura TL, auto trans, and I have unfortunately endured some issues with it.. In the morning when I start the car it sometimes hesitates to start, but once it does it shakes for about 30 seconds until the RPM's drop down below 1000; after that the shaking stops. Also, when I am on the highway or just driving city, when I step on the brake to stop and go to accelerate again the car hesitates to accelerate for about 2 seconds, then goes.. My gas mileage has dropped tremendously as well.. Any help or ideas??.. Thanks!

 

Ure rpms go above 1k in the summer? Unless its crazy cold near u, that aint right for idle.

 

It sounds like your EGR clog

 

Interestingly enough, I have an 04 6spd that has similar issue. It's hard to start and it feels like a very mild misfire. No CEL or any other issues. Sometimes on the freeway, it has slight hesitation.

I've always used 93+ and never driven hard. I've used 44k to see if it would help the hesitation. I've considered Seafoaming the car.

Thoughts?

 

My guess would be Accelerator Pedal Position sensor. The car will feel like it has a slight miss when you start it because the ECM will "misfire" the car to get the precats lit off and make them nice and toasty warm. My girlfriend had a similar issue with her 6MT TSX. It would idle high when you started it and then the idle would hang around 1500 RPM. I didn't think anything of it until it started to feel like it lost power and then got it back when you were cruising on the highway. So I got out my handy volt/ohm meter to check the APP sensor and sure enough it had a bad spot. Which is also weird because the bad spot was in the middle of the throttle range and it effected the idle where the sensor was in good working order.

 

Check your mounts and check for codes.

 

I don't think it would be the mounts; that would have cause vibration and not hesitation. OP is having a slow start and when cold its hesitating. However, I do agree with scanning to see if you have a code. When my EGR was acting up, it didn't show a check engine light, but as soon as I scan it gave a me a code.