Odd idling

RedVision_350 · 08-21-2007, 12:19 AM

I drive a 1994 SOHC 1.9L SL and I've been having an issue in which I think I have an inkling as to what's causing it, but I'm not sure, so here I am! When I am stopped (Like at a light), the engine will start idling high to about 1500rpms and then drops below 1000rpms. Then the check engine light comes on. This happens EVERY time it is hot outside or excessively humid. In mornings and evenings this doesn't happen, unless it's really humid out. I think it might be the O2 sensor, since hot air expands and maybe it throws it off?

fdryer · 08-21-2007, 01:01 AM

1-Engine coolant temperature sensor; How-to Tips library's first two posts.

2-Rap the throttle position sensor on the side of the throttle body with a screwdriver handle, if the idle speed changes the tps is faulty.

3-Clean the throttle body with carb cleaner if it hasn't been done lately.

4-The O2 sensor is more expensive to replace than performing all the above first and not likely to cause the erratic idling as mich as it would affect the engine running altogether.

RedVision_350 · 08-21-2007, 10:02 AM

Ok, awesome. I'll give those a shot. Thanks!

08-21-2007, 12:19 AM	#1
RedVision_350 Junior Member Join Date: Aug 2007 Posts: 31	Odd idling I drive a 1994 SOHC 1.9L SL and I've been having an issue in which I think I have an inkling as to what's causing it, but I'm not sure, so here I am! When I am stopped (Like at a light), the engine will start idling high to about 1500rpms and then drops below 1000rpms. Then the check engine light comes on. This happens EVERY time it is hot outside or excessively humid. In mornings and evenings this doesn't happen, unless it's really humid out. I think it might be the O2 sensor, since hot air expands and maybe it throws it off?

08-21-2007, 01:01 AM	#2
fdryer Super Member Join Date: Jan 2006 Location: NYC Posts: 45,886 fdryer's Photos 2003 L-Series 3.0L Sedan	Re: Odd idling 1-Engine coolant temperature sensor; How-to Tips library's first two posts. 2-Rap the throttle position sensor on the side of the throttle body with a screwdriver handle, if the idle speed changes the tps is faulty. 3-Clean the throttle body with carb cleaner if it hasn't been done lately. 4-The O2 sensor is more expensive to replace than performing all the above first and not likely to cause the erratic idling as mich as it would affect the engine running altogether. ... VCX NANO

08-21-2007, 10:02 AM	#3
RedVision_350 Junior Member Join Date: Aug 2007 Posts: 31	Re: Odd idling Ok, awesome. I'll give those a shot. Thanks!

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