Questionactually I think it feels more like the rumble strip that a misfiring of the plugs. What would I need to do about the torque converter?
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-----Question-----
my sonata has been acting funny lately when I am either going uphill or going straight but maintaining a steady speed between 35-40mph. It will start jerking and missing. I can't tell if it is the transmission or the engine. Any other speed it will not do it. Any ideas?
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Torque converter slippage issues on Hyundais tend to feel more like rumble strips than misfires, so I'd primarily suspect you're dealing with a misfire issue. Misfire issues tend to be worst under high load low rpm situations. Start by checking the plugs, wires, and coil to see if you can find anything. If you're going to go so far as to pull the plenum to check the rear bank, you might wish to consider just replacing the plugs and wires. That would be a lot of effort to go to without replacing the parts.
AnswerCheck your transmission fluid. If anything at all appears abnormal about it, have your transmission flushed by a dealer. The reason I specify a dealer for this is that it's important to have the correct fluid in the transmission. Torque converter slippage or shudder is the reason Hyundai originally moved away from Dexron. Once that's done, drive the car for an oil change interval or so. It's possible that installing the correct fluid (if the wrong fluid was in the transmission) will correct the issue over time.
If you've got a torque converter shudder that won't go away, you should probably consider replacing the transmission. You can get just a torque converter, but (based on dealer prices) a remanufactured transmission (with converter) doesn't cost much more than a converter.
