Tach needle jumps up and down??
06-23-2009, 10:31 PM
#1
Safety Car
Thread Starter
Tach needle jumps up and down??
Hi everyone! Its been awhile since I last visited. I have a problem with my engine. The tach needle will jump up and down, the engine would struggle like it wants to shut down but it changes its mind back and forth when I turn on the A/C. When I turn off the A/C, its fine. I notice this happening when I'm in 1st gear or at a stop light. It does not happen when I'm already driving at high speeds, 30+. What is the problem?
06-24-2009, 07:15 AM
#3
'13 Hyundai Sonata
I had this problem. Remove your intake and clean the throttle plate and bore with some throttle body cleaner. Once you do that your idle will go back to normal.
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06-30-2009, 01:00 PM
#8
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I've noticed this problem because I've been driving the TL this past week. If I leave the car running in park with the ac on the idle drops to like 500 and feels like the car is going to stall. I guess its time to start cleaning the intake manifold.
06-30-2009, 03:29 PM
#10
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Well I changed all the fluids and cleaned the TB about 10k miles ago. After that the car ran great, but now when the ac is on the car idles at 750 like normal and will occasionally drop to 500 making the car shake. If I step on the gas it'll go back and stay at 750.
06-30-2009, 07:49 PM
#11
Idle air control valve (IACV) is not compensating by allowing more bleed air=more rpm when load is added (AC). IACV is either gunked up and frozen (clean w/ throttle body cleaner) or has electrical fault (check solenoid resistance, if open replace IACV, if low resistance check that battery voltage will cause solenoid valve movement to move (after cleaning).
good luck
good luck
06-30-2009, 08:37 PM
#12
Khmer Pride
Idle air control valve (IACV) is not compensating by allowing more bleed air=more rpm when load is added (AC). IACV is either gunked up and frozen (clean w/ throttle body cleaner) or has electrical fault (check solenoid resistance, if open replace IACV, if low resistance check that battery voltage will cause solenoid valve movement to move (after cleaning).
good luck
good luck
07-29-2009, 10:31 PM
#13
Safety Car
Thread Starter
Idle air control valve (IACV) is not compensating by allowing more bleed air=more rpm when load is added (AC). IACV is either gunked up and frozen (clean w/ throttle body cleaner) or has electrical fault (check solenoid resistance, if open replace IACV, if low resistance check that battery voltage will cause solenoid valve movement to move (after cleaning).
good luck
good luck
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brandnewcolony
3G TL (2004-2008)
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09-12-2015 10:39 AM
