Unstable idle speed, excesive engine vibration, some of white smoke during warm up operation, noisy valves, recently i have chaged the fuel pump and all filters,when i stop vehicle and release the brakes the engine rpm,s increase slightly, no problems with the engine cranking, i hope your help soon and thank u!!! jonathan cordero elantra 1500 sohc injection 1992 year

Hi there! I have the same Issue. Did you find the problem by any chance?

hi, i would like to advice you check the electronic idle speed control valve and also check engine coolant temp sensor. The ISC (idle speed control valve) is located somewhere below the throttle valve. the engine coolant temp sensor is located near distributor. it has a two wire connection. the sensor connector is usually green

Smokes can be of three colors.
1. White smoke.
Excessive white smoke reveals presence of water in fuel, thermostat valve stuck open, or burnt cylinder head gasket.
2. Black smoke.
Black smoke could be observed due to the unburnt fuel or higher percentage of Hydrocarbons during the combustion process, defective regulating valve, ruptured PCV valve, low fuel pump pressure, defective charcoal canister, ruptured or leaking fuel injectors.
3. Blue smoke.
Blue smoke reveals the engine failure.

Possible dirty throttle valve and idle speed control valve.

Throttle Body Cleaning on vehicles without electronic throttle control (most 2003 and down)

You can in most cases repair this slow speed stall or unstable idle by cleaning the engine throttle valve and the idle speed control valve using a product called CRC Spray Throttle valve cleaner. Spray the cleaner into the air intake of the engine with the hose removed from the throttle body, the engine will try to stall so hold up the idle speed manually. Once you have used up about 1/2 can of the cleaner stall the engine out while spraying and turn the key off, disconnect the negative battery cable for 5 minutes and then reconnect and drive the car for a about 25 miles of varied driving modes. If this doesn't cure the problem you may need the fuel injectors professionally cleaned by the dealer service dept.

indicates an engine oil comsumption, for excesive piston rings wear or valve seals, maybe your engine neeed to repair

2 airflow sensor out of operating range 3 coolant temp sensor out of operating range 4 oxy sensor indicates full rich 5 throttle potentiometer/airflow sensor... (low throttle pot signal with high airflow sensor signal) 6 throttle pot/airflow sensor...... (high throttle pot signal with low airflow sensor signal) 7 throttle pot...idle fuel adjustment failure(idle speed??) 8 intake air temp sensor...open or shorted circuit to sensor 11 Throttle pot at idle: Throttle pot idle trim out of normal range 12 Airflow meter: MAF signal out of range 14 Coolant thermistor: Resistance out of range or static during engine warm up 16 Air thermistor: Resistance out of range 17 Throttle pot: Out of range 18 Throttle pot/Airflow: Low throttle pot signal at high airflow 19 Throttle pot/Airflow: High throttle pot signal at low airflow 22 Fuel pump drive: ECU output to fuel pump relay 23 Fuel supply: Engine running too rich 24 Ignition Drive: ECU output to ignition Amp 26 Air leak: Engine running too lean 29 ECU self check 33 Injector Drive: ECU output to injectors 34 Injector: Looks for Injector dribble 37 EGR Drive: ECU output to EGR switching valve 39 EGR check sensor: EGR not working (normally pipe blocked) 44 Lambda (O2) sensor: Poor mixture control rich or weak (or misfire) 46 Idle speed Control valve: ECU output to Coil AB 47 Idle speed Control valve: ECU output to Coil CD 48 Idle Speed Control Valve: Stepper motor grossly out of position 66 Air pump: ECU output to air pump relay 68 Road speed sensor: Seen speed < 5km/h at high engine airflow 69 Drive/Neutral switch: Seen cranking in "D" or high airflow in "N" 89 Purge Valve drive: ECU output to purge valve
this is all I could find

white smoke? Thats an indication of water getting into cylinders. May have a small head gsket leak. Metals expand when heated which explains why it stops smoking after warming up. Have some one pressurize the cooling system when engine is cold, and search or listen for leaks. Pressure gauge on tester will drop in pressure if leak is present.

If your engine is not misfiring but it vibrates too much while idling your motor mounts might be getting worn out. I had a Nissan with bad motor mounts. I was ok in park but when you put it in gear it vibrated a lot. It smoothed right out as soon as you started moving.

White smoke usually occurs when there is not enough heat to burn the fuel. The unburned fuel particles go out the tailpipe and typically produce a rich fuel smell. It's not unusual to see white smoke in the exhaust during cold weather until the engine warms up.

Faulty glow plugs or control module can cause white smoke on engine start up.

Low engine cranking speed may also produce white smoke.

If white smoke is still visible after the engine has warmed up, the engine may have one or more bad injectors, retarded injection timing or a worn injection pump.

Low compression or air in the fuel system can also be a source of white smoke.