Can an irratic IAT reading cause a stumble? I have been looking at datamaster files for two weeks trying to locate the stumble and I think I may have found it. Looking at datamaster my IAT readings will jump as much as 30*F in less than a second. Normally right after I blip the throttle. The stumble seems to be worse after the engine goes into closed loop. I have looked at previous files and this erratic reading is not there.

 

If you have something broke, fix it. That's alway my rule.

 

I completely agree. Just have to get some time after work and some daylight. Doing elec repairs in the driveway after dark near winter isnt my idea of fun anymore. I was just curious if this could cause it

 

It takes a couple of minutes to replace an IAT. Once that is done, you can see if that helps. It's a possible solution to your problem.

 

Well I have a new sensor and new pigtail installed thanks to your website part numbers and I still have an IAT fluctuation reading. I was curious how much the reading should change as the car warms up and during driving

 

The inlet air temp generally will slowly drop as you drive at higher speeds, reducing the heat soak in the sensor and elbow. When you sit in traffic, the sensor will heat soak, and can increase 20-30* over a period of several minutes.

But it should never change by 30* in a matter of less than one second. If the sensor isn't bad, then the wiring is loose, the harness connector pins are corroded, or something else is intermittently changing the resistance in the circuit.