Engine starts, but no idle

[zzb3886]

My '00 XLT sohc (already 100k) has sit there for a rainy week, and now it has idle problems. When I start the key, the engine starts and gets up to 1k+ rpm. It then drops below 500 rpm within 2 seconds and dies. Shakes heavily. The only way to keep it alive is to hold the gas pedal all the time. The IAC has just been changed, and if unplug the MAF, it idles but rough. I'm not sure whether the intake o-rings have been updated.

I'd like to rent a OBDII scanner and read the code before doing more checking. However the check engine light is not on -- does that mean currently there is no trouble to be read?

 

[BrooklynBay]

You might have a stored code for the MAF now since it was disconnected. Did you check the vacuum lines for cracks? Was the fuel filter ever replaced?

 

[seth247]

autozone will read codes for free.

 

[zzb3886]

So, not all the codes trigger the check engine light, do they? I may as well rent a scanner since the truck can't be driven like this. I got the truck a short time ago, I don't know the exact status of the fuel filter. Needs to be checked. And the vacuum lines too.

 

[BrooklynBay]

Not all scanners are capable of reading every code.

 

[zzb3886]

You mean some P0XXX trouble codes can't be read by some scanner? I thought every scanner could do that, and some advanced ones could read sensor data.

 

[BrooklynBay]

Some examples of things that not all scanners could read are manufacturer specific codes, ABS codes, and SRS codes.

 

[zzb3886]

Good to know. Thanks!