1988 190e 2.3 Engine hesitation ??
 

The engine just started hesitating when I accelerate from a standing start. If I slowly press the pedel it will run just fine. It almost feels like its starting in 2nd(automatic). Just the other day it gave me problems starting and I tapped the pedel quickly to get it started... Any ideas? I have been reading through the responses and there are lots of ideas. I had a similar problem with my Camero and I found my low fuel pressure. A new pump was the cure....
Any solid ideas are appriciated.
Nellie

Sounds like the airflow meter is going bad!! If the car has more than 100K miles on it and has never been changed then its a pretty good bet that it needs one.

You can actually test the air sensor potentiometer if you are equipped to do some electrical testing.

Basic tune up stuff should first be ruled out by just replacing them: air filter, spark plugs, distributor cap and rotor.

There are a few sensors/switches that can be tested to rule out some more possibilities.

Coolant temp sensor is another possibility.

These are the answers I was looking for.
 

Thanks, I will get busy looking into some of these varibles and see what is left. I don't know the porcedure to electrially test air sensor but I will read through my Hanes manual and online. I appreciate the ideas. Bob

Assuming your car's sensor is similar to my 87, 260E.

At idle, the middle terminal on the sensor should be between 0.5 and 1V. Then as you gradually depress the gas pedal, the voltage should smoothly rise. There should be no erractic change in voltage.

Also for the above test, the 3 terminals of the wire connector must be connected to the 3 terminals of the sensor, so use some alligator clips.

If you dont get any voltage, check the third connector, it should have close to 5V. This 5V comes from the ECU via the wiring harness.

Also if you have erratic voltage on middle terminal, disconnect the wire connector and check resistance between middle and the third terminal on the sensor. Can can be off. When the air sensor plate is on the top, the resistance should be between 1 and 2K. Now gradually push the plate downward, the resistance should gradually increase. There should be no jumps greater than 4K. Otherwise, the pot needs replacement.