My 01 Sonata v-6 when it upshifts it will attempt to make the shift pause then stay in its current gear for another 3-500 rpm then make the shift. It pauses long enough the first time it did it I thought it died. And it doesnt matter what gear its shifting into. But it never throws a code. The car just turned 60k and had the Tranny flushed at the dealership @ 46K :3gears:

This post has been edited by 71mopar383: Jun 5 2008, 08:28 PM

sounds like you're runnin into the headache many of us know
its possible its one of the speed sensors or the tps,all of which are easy to replace and generally can be found online for under 150bucks

definately sounds like the problem

Hi, just thought i'd put in my 2 cents worth on automatic shifting problems with the sonata (EF-A model). I recently had both Input and output speed sensors go bad. The output speed sensor went first and would fail after the car warmed up. The usual symptom was bad 1-2nd shifts followed soon after by limp mode (stuck in 3rd). The bad shift is like it goes into nuetral and revs high between gears, like a bad manual gear change. Restarting the car will fix it for a minute or so. Soon after the input sensor went, these symptoms were more serious high idle, thumps into gear when coming to a stop and very poor gear changes. Combine the two and its lots of fun. I picked up new sensors from a 2000 model sonata at the wreckers these appeared slightly different with a continuous barrel on the end rather than small diameter cylinder sticking out of a larger diameter cylinder holding the o-ring.

Changing the sensors is dead easy, although make sure you remove the battery to get at the last of the bolts holding the air box in (added benefit is that the computer then needs to relearn shifting).

You will need a socket set or extensions to get at some of the bolts. BTW the output speed sensor is the more outboard of the sensors on top of the trans casing, the input speed sensor is almost directly under the end of the engine.

Changing them fixed all the problems and cost me only $15.

Hope this helps someone, Jim

So I changed the input and output sensors and still it pauses and you think its going to upshift and it stays in the same gear. It looks and feels like a stick shift and you have it say in 1st gear and you get on it then let off then get on it again and you get that jerk feeling that what i have. what next a TPS? or should I try and get a rebuild before my 10/100000 warr is up? :beer:

Have you replaced TPS? If you fix the problem, could you tell me what you did? Is there way to diagnose those speed sensors with logging the output of OBDii scanner? I recorded output of TPS in %, it seems OK. I didn't see any spark.

This post has been edited by sagittager: Nov 15 2008, 06:12 PM

Im getting random Hi idle, intermittent. It revs upto 3000 sometimes and sometimes not, i did my Fuel Pump, and Output speed sensor. The input causes the Hi idlling that makes it feel like it wants to stall when hitting the gas on take-off? I do get the downshift bumps