2003 Accord V6 hesitates during acceleration when cold

I have a 2003 Honda Accord V6 that has some acceleration hesitation and general jerkiness, usually noticeable when the car has been sitting for a long period of time (overnight). The symptoms seem to dissipate after 5 - 10 minutes of driving.

When I begin accelerating, the car feels like it hesitates when shifting from 1st to 2nd gear. If I let off the gas a bit, then the car jerks a bit.

I’m sure it’s not the transmission, because the dealer said the fluid and everything looks fine. Additionally, I have another Accord (2000) that does have a failing transmission and the symptoms on that one are very different from this 2003.

A couple of months ago, I was getting a CEL and had a friend of mine read the code with his OBD tool. It indicated that Bank 1 Sensor 1 was bad. I replaced it with a Denso. I think the problem got better at that point, but has “worsened” again over the past month or so.

Any clues what this might be? Things I can try? Ways to narrow down the issue?

Thanks in advance!

Some things to have checked is the fuel pressure/volume, and the coolant temperature sensor for the computer.

When the engine is started cold , the demand for fuel to the engine is at it’s greatest. If the fuel pump is weak where it can’t deliver the proper amount fuel pressure/volume to the engine it can cause the engine to lay down or stumble under acceleration.

If the fuel pressure/volume is fine, then the problem might with the coolant temperature sensor for the computer. If this sensor is sending an erroneous signal to the computer where it’s telling the computer that the engine is up operating temperature when it’s not, the computer won’t deliver enough fuel to the engine when it’s cold. And the engine can lay down or stumble when accelerating.


In addition to what tester said, the transmission in this vehicle has a history of cold shift problems. Honda has come out with a new ATF called DM-1. Just one drain and fill with this new ATF will do wonders for the cold shift problem. The DM-1 is fully compatible with the older Z-1 ATF so you don’t need a flush. But this is only for the 1-2 stumble, go with tester on the rest of the problem.

The Accord auto transmission fluid change is repeated 3 times. Drain, refill, drive a little, and repeat 2 more times. Leave the fluid in after the 3rd refill and top it off after the last short drive. BTW, you pour the transmission fluid in through the dip stick port. You need a funnel that fits in that narrow hole.

“…new ATF called DM-1.”

That would be DW-1.

I stand corrected, DW-1, must be the dyslexia. The three changes are if you have neglected the ATF and need to do a more complete change out. I took care of my transmission so when the DW-1 came out, I just did one drain and fill and it made a big difference in the Honda’s cold shifting issues. Not a complete cure, but huge improvement.

I change my oil every 30,000 miles and only do it once. If you go the 90,000 miles that Honda recommends, it should be done 3 times. It’s in the owner’s manual! Who’ think of looking there? :wink:

“I change my oil every 30,000 miles and only do it once.”

I REALLY hope that you are referring to transmission fluid, rather than motor oil!
Otherwise, you will be the next person posting here about engine sludge problems…

(Yes, I know that you were talking about trans fluid)


Oops… Correct.