Mechanics

HIGH IDLE

2004 Saturn Ion

Electrical problem
2004 Saturn Ion 60,000 miles

sudden acceleration problems for several years. It is not necessary to even touch or move the accelerator pedal in order for this to occur. Under certain conditions of temperature and humidity, either some sensor malfunctions or some connector becomes intermittent or the software misreads something. At startup the engine runs at an unusually high idle (~800 rpm), and as soon as you put it in gear, the car lunges forward or backward hard and you have to put it in neutral to avoid having it run away with you - all this without touching the accelerator pedal. When you put the car in neutral the engine runs at between 3,000 and 4,000 rpm on the tachometer for a few seconds and then slowly drops back to an idle (~800rpm). As soon as you put it in gear again, the car lunges once again -
It gets really bad when driving uphill. It gets stuck at 4000 rpms and when I take my foot off, it stays there and I have to press the break really hard. Sometimes, the rpms override my trying to brake! Help. I think this is a computer or software problem I have no check engine light. When I reset the battery, it helps for a few days. The tps sesor seems ok. Thanks denise
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Denisesmith124
October 14, 2010.



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