Cold Stumble

[scotschult]

My G/F has a 94 CV which has developed a stumble when cold. When started from "cold", car will idle fine, but when accellerating will stumble & backfire badly, until car reaches about operating temp, when it will run/accel fine. Mileage has also gone down badly. No codes are set, although she says she has seen the Check Engine light once. Plugs & wires were replaced this spring with Motorcraft to fix a dead wire. I first suspected the Temp Sensor, however a resistance check of it is within spec., and all wiring looks good. Temp reading thru a scanner also looks good. Fuel pressure is rock steady at 40 psi. I've read about a number of issues with the IAC, and am also wondering about the Crank Sensor, but can't convince myself of these due to the symptoms (cold, accel'ing). Any thoughts/input is appreciated!

[way2old]

You may want to look inside the throttle body and see if it is dirty. It will tell you not to clean it, but todays chemicals are ok to use on it. They put that sticker on there to keep people from using carburetor cleaner and brake cleaner.

[danielsatur]

I would also try cleaning the MAF sensor with CRC MAF sensor cleaner.

If you still have the problem after cleaning, I would replace the bad MAF sensor.

[scotschult]

My apologies! I could have sworn I posted the fix to this!

Mass Air Flow Sensor. Found a "quick & dirty" test online. Unplug the sensor, and see how it acts. So, I unplugged it, and the car ran like a scalded ape. Sprayed it out with some MAF Cleaner, and the car is almost like new.