Problems · by component
2018 Hyundai Sonata fuel/propulsion system problems
32 owner complaints to NHTSA about the 2018 Hyundai Sonata cite fuel/propulsion system, 9% of all 375 complaints for this model year.
Complaints
32
9% of all complaints
Crashes
0
Reported by owners
Fires
1
Reported by owners
Injuries
0
Reported by owners
What owners say about the fuel/propulsion system
Verbatim from NHTSA complaints, newest first
“The vehicle experiences a severe delayed start/extended crank condition before finally starting. This is caused by a loss of fuel pressure prime due to the defective fuel filter housing leaking internally, creating an unpredictable and unsafe vehicle operation hazard. The dealership is denying coverage under the 15-year/150,000-mile extended warranty (Campaign TXXS), claiming the issue is a standard fuel pump failure while completely ignoring that the integrated fuel filter housing defect causes this exact failure."”
“My car stalls while driving and then I try to restart it but nothing happens. After reading online about the fuel pump issues and extended warranty related to the fuel pump I took the car in for repair. My car has 75,000 miles and the extended repair on this is for 150,000 miles/15 years. The dealer is refusing the repair because my car has a branded/ theft title. The car wasn't damaged just stolen. This is creating a serious safety concern and should be repaired by the dealer. Thank you for your time.”
“Engine blown out malfunction took two dealer Hyundai Folsom Lake stated rings are bad sludge buildup in engine and stayed at Hyundai motor America denied engine replacement due to knowledge under Theta two engine extended warranty settlement of 150,000 MI 15 years I'm still within warranty but are still being denied had numerous of issues with vehicle oil consumption knock knock sensor replace and other maintenance done since purchase vehicle brand new in 2018”
“I am submitting this complaint to report a serious and ongoing safety defect involving the engine of my 2018 Hyundai Sonata Sport equipped with the 2.4L Theta II engine. The vehicle has been officially tested and documented by Hyundai as consuming more than two (2) quarts of engine oil per 1,000 miles, which Hyundai has acknowledged following completion of its oil consumption test procedure. Despite this confirmation, Hyundai has declined to fully correct the defect. As the condition has progressed, the engine now fouls spark plugs every 350–500 miles, resulting in: •Engine misfires •Loss of power during operation •Rough running and hesitation •Risk of sudden engine stalls while driving This condition occurs without warning and requires repeated roadside or emergency repairs simply to keep the vehicle operable. The condition has deteriorated further, requiring replacement of fouled spark plugs every 350-500 miles. Loss of power and engine shaking can occur at any time, presenting a safety hazard for me and other drivers.”
“Throttle response intermittent problem no acceleration since new. No codes available. When entering traffic engine stall factor flat spot. Been to dealer many times (Bud Clary) and just recently (04/26) confirmed the fuel pump is the problem. Unable to confirm because of no "codes". Will not replace or register for recall without proper codes. No check engine lamp. No inspection by police or insurance only the dealership service department is aware of the problem.”
“Had an oil change, then 2 weeks later car making noise, checked the oil and it was completely empty, so we refilled the oil. Then a month after again same issue no oil, refilled it again and now a week later it's 2 quarts low already. Also when I come to a complete stop when it is time to go again it's very slow at going or if I try to excel it takes it a very long time to actually excel I think something's wrong with the fuel pump”
Showing 6 of 32 reports. Read every report on NHTSA.gov.
Data from NHTSA Complaints API (owner reports, unverified) · synced Nov 9, 2026NHTSA vehicle page
Complaints are unverified owner reports to NHTSA and are not normalized for sales volume. One complaint can cite several components.