300CE won't accelerate on 100 deg. day.
 

This is my first summer with the 300CE. A few times while driving in really hot weather (about 100 degrees) it has refused to accelerate from a stop. The problem is intermittent and it's only happened about five times so far.

I can't quite tell if the car just has no power, is in the wrong gear (failed to downshift when I stopped), or what. It doesn't shake like the engine is about to stall. It doesn't cough or sputter when I hit the gas, it just doesn't go anywhere.

If I stand on the accelerator and force a downshift to 1st gear, the car will accelerate, although it is sluggish at tip-in. Once it gets to about 1000 RPMs it's back to normal.

Again, it only seems to happen on really hot days in mild stop-and go driving. (City streets, but not gridlock - I'm in Oklahoma) I'm running the A/C full-blast, but coolant temp is normal.

Is it simply time for a tune-up? I can't verify whether the PO did one.

Check your fuel pump output -- I had an Audi Fox that exhibited similar symptoms (although it usually quit completely most of the time) when the fuel pump was going out. Worked fine until I got to Tulsa on a long trip -- croaked on the freeway in rush hour traffic in a construction zone. When it (and we) cooled off, it was fine.

Certainly sounds like a fuel problem.

Peter

Also, Check your coolant temp. sensor. Mine did the same thing and I found the connection was loose.

Okay, I noticed something else today that I figured was unrelated, but it might be worth mentioning just for giggles...

My fuel gage has started jumping erratically. Basically it will drop to the bottom for a second and then back to normal, or jitter several times between normal and empty. I expect it's just an intermittent electrical connection. I recently repaired the speedo, so I could have screwed something up when I reassembled the panel.

Even a small chance there could be a connection?