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Greg
Greg, import technician
Category: Hyundai
Satisfied Customers: 6806
Experience:  27 year and 16 year as shop owner, import technician
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2002 Hyundai Sonata: cylinder..check engine light..accelerating

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I have a 2002 Hyundai Sonata 4 cylinder... The check engine light is not on. When accelerating it takes a while to catch up to speed. When hitting a higher speed the car jerked. Going up hill the car atalled out, was able to turn it back on and continue going up hill at a slow speed. There was almost a full tank of gas in it and I had the fuel pump checked. Mechanic said it was fine. Check engine ligght came on for a little bit and the scanner read that there were mulriple misfires but went back off. What could be the problem? We've coincidered an 02 sensor and coils but dont think those are the problems..?? can you help please??
Hi welcome to JA.com.I will answer your question the best I can,

When the fuel pump was checked did he do a fuel pressure test ?

This sound like fuel related problem .

Regards Greg
Customer: replied 5 years ago.

No he did not. He will be checking the fuel pressure tomorrow. He said the fuel pump is working though and was wondering if it could be jumped time?

Hi

Fuel pumps can work and still not give the correct amount of pressure needed.

Best test is with a running engine .

Running engine vacuum hose disconnected 47-50 psi
engine vacuum hose connected 38 psi


Kind regards Greg
Customer: replied 5 years ago.
Okay after the fuel pressure is checked... if its not correct what needs to be changed? and if it is correct any other suggestions that could be causing the problems??
Hi

If pressure is not correct (low) slow in rising to pressure needed check fuel filter .

replace fuel pump if filter is good.

When fuel pressure is ok :

  • MAF mass air flow sensor.
  • Possible vacuum leak.
  • Engine coolant sensor.
  • Engine management system, wiring, harness, connections .
  • ECM malfunction .

Kind regards Greg
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