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350matt, Engineer
Category: Hyundai
Satisfied Customers: 21628
Experience:  Mechanical Engineer BEng Hons 22 years experience in car engine industry, 10 years in formula 1
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I have a 2010 hyudai accent, manual transmission with 60,000

Customer Question

I have a 2010 hyudai accent, manual transmission with 60,000 miles.
It is experiencing intermittent problems. Have brought to three mechanics and none has been able to find issue.
1. Car will buck for about one second
2. Tachnometer will drop to zero, even though driving a 60 or more. Not related to the buck.
3. Shift indicator will flash both up and down at the same time, despite going 60 in 5th gear.
4. Entire car will shut down once slow down/stopped. Will start as though nothing wrong 30 minutes or more later.So far spark plugs and all ignition coils have been replaced. Still having the problem.Any idea is appreciated.Thanks,
Submitted: 1 year ago.
Category: Hyundai
Expert:  350matt replied 1 year ago.


This could be a wiring issue as things tend to expand when hot and its possible a poor or partial electrical connection is being pushed apart on one of the major sensors so check the connection plug and wiring to the following;

Airflow meter

Crank position sensor

Cam position sensor

O2 sensor

Throttle position sensor

unplug each in turn and use some switch / contact cleaner spray on the pins to ensure its all grease / dirt free

Also worth checking the connections to the fuel pump for the same reason - unplug each in turn and give them a good squirt of switch / contact cleaner - Not WD40

and also unplug and inspect the main power relays and fuses for signs of overheating or corroded terminals - so the ones for the ECU and the fuel pump

Also its worth checking that the electric pump that feeds the injectors is working correctly, it should run for a few seconds then switch off when you first turn the ignition on. If the connections to this are corroded or damaged then the pump could stop at any time. Check that its relay switches in and out and the relay contacts are clean and bright – replace the relay if in any doubt and do the same for the fuse, ideally measure the voltage at the pump and check its getting 12V

Customer: replied 1 year ago.
This has all been checked by my mechanic and found to be in good working order.
I took it to another mechanic who thought it might be ignition coils, as they were cracked, but after replacing, I am still having the same issues.Any other idea?