baldmike73

My fiancee has a 99 C280 Sport and every once in a while when driving in the morning the car seems like it will shift hard/early and it usually does it while under 20mph. Anyone else ever have this happen to them?

TIA
Mike

RunInColorado

I have a similar issue with my 98 C230. I figured I was just being too much of a lead foot and backed off a bit. I have heard (or maybe read in the owners manual) that the car will upshift early when the engine is not fully warmed up. I could be wrong though with that though. Anyone else with the same issue?

scorchie

You are correct, when the car is not warmed up, upshift is delayed to give the catalytic convertor more time to warm up to reduce emissions. This can cause a hard upshift due to the higher RPMs.

I find in the Bay Area it's never so cold that letting the car run 30 seconds before driving away won't completely eliminate this.

-s-

baldmike73

Thanks for the replies.
That helps alot.


Mike

jfcarli

My 99 C280 has done this quite a bit. I brought it to the dealer just after I got the car. It's just something to live with.

RunInColorado

Thanks everyone, cleared that one right up. Glad I remembered correctly.