1997 Hyundai Elantra codes P1128, P0455 and P0707. Car seems to be stuck in 3rd gear. Check engine light on. Doesn't want to accelerate, sometimes the pedal goes all the way to the floor when accelerating from a stop, and nothing happens. Then it kicks in and starts moving, very slowly, but the rpms go up. Bucking and hesitating while moving. Can't give it too much gas from a stop, or it just bogs. Have to push the accelerator very slowly. Once I can get it moving, seems fine on the highway, at a constant speed, but revs very high. When I can get it to run, I'm red-lining at 65 mph, around 4000 rps. Fuel smell inside and outside of the car after fill ups. Please advise, and thanks in advance!

Hi, the trouble codes P1128, P0455 and P0707 is a summary of all the problems your are currently experiencing with the car and each code will be explained in details below...

P0455 This indicates a fuel vapor leak or lack of purge flow in the EVAP control system. It means a large leak has been detected. The (EVAP) emission control system prevents the escape of fuel vapors from a vehicle's fuel system. Fuel vapors are routed by hoses to a charcoal canister for storage. Later, when the engine is running a purge control valve opens allowing intake vacuum to siphon the fuel vapors into the engine.

A loose or improperly affixed gas cap
A non-conforming gas cap (i.e. not factory/original brand)
Other leak or damaged piece in EVAP system



P0707 The park/neutral position (PNP) switch includes a transmission range switch. The transmission range switch detects the selector lever position when the shift lever is in the N or P shift position and sends a signal to the Transmission Control Module (TCM).

- Open or short park/neutral position switch circuit
- Poor park/neutral position switch circuit connection
- Misadjusted park/neutral position switch
- Park/neutral position switch may be faulty

Code P1128 is a lean condition code. The engine computer may be reducing boost to protect itself. Assuming the parts you have replaced are in good working condition I would check the fuel pressure (pump failing?) check the oxygen sensors (switching throughout full range?) and check the operation of the fuel injectors (not spraying correctly).