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Category: Car
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Experience:  33 years exp. automotive repair NYS emisisions repair cert.
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98 Hyundai Sonata Gl: 3000rpm..throttle..low engine power..rough idle

Customer Question

98 Hyundai Sonata Gl, will not rev past 3000rpm at WOT. Will rev past 3000rpm with partial throttle (25%). Very low engine power with rough idle.
Submitted: 11 years ago.
Category: Car
Expert:  Marc replied 11 years ago.
 

4 or 6 cylinder?
Customer: replied 11 years ago.
Reply to enginboy's Post: 4cyl. Problem increases during operating temp. I have replaced spark plugs, spark plug wires, fuel filter, and torque converter. I have a feeling it has to with the o2 sensor.
Expert:  Marc replied 11 years ago.

 

what happens when you reach 3000rpms dose it hold steady ? stumble? go up and down? Get back to me.


  You are probably going to need a multi meter that is capable of reading duty cycle- frequency.

Customer: replied 11 years ago.
Reply to enginboy's Post: Once it reaches 3000rpm (20%+ throttle) it more or less surges, then slowly drops to a rough idle. When less than 20% throttle, it revvs normally, no funny sounds.
Expert:  Marc replied 11 years ago.
  Dose the check engine light come on?  

Customer: replied 11 years ago.
Reply to enginboy's Post: actually. . . the check engine light has been on for months now. Since, we have replaced the transmission (8 months ago), timing belt (4 months ago), and recently a new torque converter, starter, and of course normal maintenence.
In fact, today, I rented a code reader from a local Auto Zone. It came up : p0443 - Evaporative Emmission control system purge control valve circuit malfunction.
My assumtion is that the PCV needs replacing, but I don't know. Could it be anything else, even though it sends this particular error code?
Expert:  Marc replied 11 years ago.

 

The pcv has nothing to do with that code. The problem is more likely to be the purge solenoid or it's circuitry.


  If that scanner gives you sensor values(witch I doudt) see what the mas air flow sensor is doing when the engine screws up while reving.

Customer: replied 11 years ago.
Reply to enginboy's Post: Yeah the scanner doesn't give sensor values, and I have already returned it.
Today I talked to a local Hyundai dealership and they said that it was under a recall. I'm going to take it in friday to have them look at it. They said that if it's emmissions related, that it was part of the recall.
Would a MAF sensor be part of emmissions?
Expert:  jon_050 replied 11 years ago.

Gtspaul,


 If you don't mind offering some information, how much did it cost to rent the scanner from autozone. I have been told they started renting (actually a fully refundable deposit?) the scanner because the gov is stopping them from clearing trouble codes so their (consumer friendly) response is to let you borrow the tool and do it yourself.

Customer: replied 11 years ago.
Reply to jon_050's Post: you're correct! I rented the scan tool for $175.00. . . when I returned it (later that day) I received my money in full. another option was free usage in their parking lot. In fact today I was talking with one of my buddies, who works for a "chevron quik oil stop" where they do smog inspection. I don't know how the emmission laws are in new york, but here in california they have gotten strict. It used to be only the tail pipe sniffer, but now it requires a full diagnostic test. They hook up to your ECU via OBDII port and take a full reading of all sensors and statistics. They can tell (and will fail you) if your check engine light has come on and been turned off right before an inspection, you have to put miles on the car first so that the computer can recognize if the problem has been fixed.
Expert:  Marc replied 11 years ago.
 

The MAF sensor is probably covered but there are time and milage limitations  I think you have time but don't hold me to it. Enginboy

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