I have a 2006 Hyundia Sonata. I idles really bad like you pulled 5 of the six plug wires off when you put it in gear. Once you start moving a couple miles an hour it is fine. It is also perfect in park or neutral, not a hint of a problem. Put it in drive or reverse and it almost stalls.
amontello
have the spark plugs ever been changed before?
i know on mine that i had changed them to e3s and about a year an 14k miles it started have a super rough idle in drive and sometimes it began to spit like all the cylinders werent firing correctly until engine speed got up above 1800rpm at partial throttle but after i changed em back to ngk LI's it was like brand new again hah so you might wanna try that
i know on mine that i had changed them to e3s and about a year an 14k miles it started have a super rough idle in drive and sometimes it began to spit like all the cylinders werent firing correctly until engine speed got up above 1800rpm at partial throttle but after i changed em back to ngk LI's it was like brand new again hah so you might wanna try that
I just noticed today that the problem seems to be an idle problem. When you put it in drive the rpms go up. You have to hold your foot on the break to keep from taking off. If you take your foot off the break it will go up to about 35 mph on a flat road. If you keep your foot on the break the motor starts to ping and run rough.
In gear at idle. It runs like it's deiseling. You know how some cars keep running after you turn them off. That's the sound and thats the roughness. It idles perfect untill you put it in gear. It then seems to try to increase the rpms, but by keeping my foot on the break so it doesn't move, it knocks and runs rough. If I take my foot off the break it moves forward and roughness goes away. It will then take you to about 30mph without stepping on the gas.
I had a very similar issue years ago, here is what mine turned out to be. Hyundai has an electronically controlled power steering pump. The system allows the pressure to change at different speeds, on the highway it turns the pressure down to allow you to feel the road better and at lower speeds it increases pressure to help you turn in say parking lots. With my car the pressure sensor malfunctions calling for the car to make full pressure at idle without and demand for steering. Because the sensor wasn't working the computer was unable to bring up the idle speed to account for the increased load on the engine, causing the engine to be lugged down and almost at a stalling point, creating the rough idle. My dealer replaced the sensor and repaired the corroded wire plug and problem was solved.
How about some maintenance history? What has been done on the car?
What is the current mileage on the odometer?
Hyundais/KIAs also need the transmission fluids drained and refilled every 30k miles. If this is not done you will end up with transmission problems similar to what you claim.
The timing belt should be replaced EVERY 60k miles. Not doing this WILL result in either heavy engine damage or a completely destroyed one.
Plugs and wires are a good cheap way to improve mileage and performance also.
Dave
What is the current mileage on the odometer?
Hyundais/KIAs also need the transmission fluids drained and refilled every 30k miles. If this is not done you will end up with transmission problems similar to what you claim.
The timing belt should be replaced EVERY 60k miles. Not doing this WILL result in either heavy engine damage or a completely destroyed one.
Plugs and wires are a good cheap way to improve mileage and performance also.
Dave
Just figured out that the real issue is it idles to fast when you put it gear. In park or neutral it idles at about 800rpms. Runs real smooth. As soon as you put it gear idle jumps to about 1200. To keep the car from moving forward you have to push on the brake. This was causing the car to "deisel" "spark knock". I changed the plugs today they were due. There is 120,000 on the car. Replaced with iridium laser plugs. Hyundia original stuf. Also replased ari filter while I was at it. The deiseling is gone but I still have the same idle problem. If I take my foot off the brake I wll go to 35mph on a flat surface without touching the gas pedal. When it reaches 35, the RPM's is about 1500. At that point the motor will surge between 1,000rpm's and 1,500 rpm's. The whole time I will not have my foot on the gas pedal. Once again when the car is in park it runs great. The only code is P00D7. Can't find out what that is.
No cable. Electronic controled. I am goung to start a new thread because I believe the problem is not " Rough Idle" but " Idle to High" I also have some new info on whats going on. I hooked my laptop up to it and got the following readings.
at Idle min at idle max at idle when it goes into gear
RPM 612 500 1255 RPM
Absolute
Throtle
Position 12% 11.8% 23.9%
Intake
Pressure 32KPA 27KPA 90KPA
Air Flow .51 lb/m .33 lb/m 3.97 lb/m
at Idle min at idle max at idle when it goes into gear
RPM 612 500 1255 RPM
Absolute
Throtle
Position 12% 11.8% 23.9%
Intake
Pressure 32KPA 27KPA 90KPA
Air Flow .51 lb/m .33 lb/m 3.97 lb/m
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