My Hyundai dealership service department has been unable to successfully diagnose a serious problem with my car for nearly 5 months and I am in need of help. Occasionally, the car will have mini-seizures (shaking terribly) when I am going uphill, only when I am pressing on the accelerator. It reminds me of popping a clutch the way it jolts the car back and forth. Usually it will happen after I have slowed down behind someone by taking my foot off the gas and then pressing on the gas around 35 to 40 mph. However, at times it will do the same thing after I turn a corner and then try to accelerate coming out of the turn. It happens more after I’ve been driving for longer periods or if it’s warmer. The problem is that no engine light has appeared nor any computer code that will assist the mechanics in diagnosing the problem. Any ideas? Thanks for your help.

 

[align=left]Hi.
I had the same misfireing problems on a ford Escort, which was mistifying the garage. It always happend when excellerating or gunning up hill, so I realised it was fuel starvation. So to test for a vacuum in the tank, I loosend the petrol cap; which cured the fault.
Trust this is of help to you.

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Do you know if they had called the Tec Assit line to find if hyundai may have a anser for you? Maybe if you could try another dealer in your area and or make sure that they contact hyundai and see if there is any issues that they may know of.

 

If you try this, be aware that your "check engine" will eventually come on. Usually shutting the engine off, tighening the cap back up and restarting solves that issue.

I suggest you do try this. If swivelcel's advice does solve the problem, take the car back to the dealer and tell them the problem is related to a plugged fuel tank vent line or malfunctioning ventilation valve that is part of the gasoline vapor recovery system.

 

Check your Personal Messages.

 

There is no personal message from you to retreive.

 

Sorry, that was for jenniepage

 

the hi-scan tool has a setting on it to see any misfires on the NF sonata. they need to drive it and watch the misfire count and it should pinpoint the cylinder.once they know what cyl is causing the misfire then they can see why by pulling the plug or moving it same goes for the coil.a small crack or carbon track will do exactly what you describe.