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Discussion Starter · #1 ·
So my hyundai was my first car.
We bought it from a broker. My parents test drove it and the car was a surprise. I loved it but soon started realizing it was driving pretty terrible. It's an automatic and the transmission is VERY bumpy when switching gears. Especially with the a/c on. About a week after getting it, the CEL went on. We were told there was no problems on the car at all. We took it into a mechanic and he said there wasnt enough pressure in one of the cylinders. I have no idea what that means but he said it would be expensive to fix. Any ideas of what to do? Could he possibly have been diagnosing my car wrong?
 

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well, i am no mechanic but i know how to get around google like i know my name.
There are three major leak paths where cylinder pressure can escape: past the rings, the intake valve, or the exhaust valve. We'll ignore the head gasket for now. With each of these three leak sources, it's easy to tell where the leakage is originating with some sleuthing. If you can hear a hissing sound coming from the valve cover breather hole or from the dipstick tube, then the air is escaping past the rings. If you prop open the throttle blades and hear that same hissing sound, then the pressure is leaking past the intake valve. If the air is escaping past the exhaust valve, you will probably be able to hear the air even as far back as the tailpipe
i got this from How to do Cylinder Leak Down Testing- Car Craft Magazine

and i have no idea what the throttle blades are. but i think they might be referencing to the round thingy that is between the intake piping and the intake manifold (i think it is like a throttle something) you know, with the silver steel string thing around one part of it. the only problem with what i think it is and the description is in the artical it was plural and there is only 1 on my car. (i told you i was not a mechanic, hehe):D
 

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I would say step one would be to take it auto zone or checker, some car place and have them check what the CEL is for. If it is anything related to the cylinders, well, there's your answer.
 

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if someone compression tested the car and one cylinder was weak than that explains itself. You have to have compression to make power. If the car feels like it misfiring(bucking/jerking) then you probably have a dead hole(a bad cylinder). Most dead holes i've seen have been caused by a valve not sealing correctly from wearing itself into the valve seat.

Now i'm not the mechanic that took a look at your car so i'm only speculating here. You could just have misfire problems caused by the ignition parts(plugs, wires, coil pack). If you don't trust this mechanic's judgement than you can always take it elsewhere for a second opinion. You can expect to pay diagnostic fees wherever you go though our charge is 69.95 for example.

If however his diagnosis is correct then you will be better off with another motor than to try to rebuild the head. When mechanical problems like this come up at my shop, if a head is rebuilt we recommend a rebuild of the bottom end as well. If your head seals well then the weak link would be your compression rings on your pistons.

I can address your shifting problems from experience owning an accent with an automatic. mine has had a rough kickdown from 2nd to 1st and sometimes 3rd to 2nd since the day I got it. Its just bad shift logic on hyundai's part. There is really nothing you can do to fix it. I've had the solenoids replaced under warranty and it still shifts exactly the same.

hopefully this will help you out some. I hope for you that you don't have mechanical problems because they will be costly. If that is the case you might want to weigh out the cost of the repair vs a nice down payment on something new.
 

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Any luck with this?
 
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