Engine symbol on dash, car sometimes idles weird, where revs go up and down. some loss of power every now and then

Always check for trouble codes when the check engine light turns on during engine running. After repairs are made, a scanner can be used to erase the codes.

It sounds like a fuel problem, so you would need to have the fuel pressure tested. This will verify the fuel pump and fuel filter are not the problem if the pressure is correct.

If the check engine light is on, you need to check the computer for trouble codes first.
The idle speed is computer controlled by the idle air bypass valve. The valve can get gummed up, and so can the throttle body.

Prognosis is really bad, hate to tell you. Ticking comes from the valve lifters, losing lubrication due to lack of pressure and running dry. At redlights, when revs are at idle, oil pressure drops a lot, and engine really suffers. Have the vehicle taken immediately to a shop for proper diagnose and to see if engine can still be saved. The loss of power comes from the valves not actuating properly. Hydraulic lifters need oil at a decent pressure to "charge" , and if not charged, they will stay compressed, ruining valve lifting operation.

Your problem could be at the fuse panel. A cheap fix is to get some stranded wire. Small gauge, like 24 or 32 gauge. Cut small pieces and strip the ends and put them down in the fuse panel where the relay goes. Then put the relay in. If this doesn't cure the problem, look to the throttle body plug. best to replace the plug. If the wire woks for the panel, Leave it or replace the fuse panel.

If the idle seemed to go out of control further then the issue may be with the idle air control valve, it may be dirty or may have gone bad. Check also the fuel filter and loose wires and vacuum hoses.

ask a, local mechanic to have a look ,i suspect the idle motor but it could be the throttle sosition sensor under the dash ,its a renault so its impossible to read any diagnostic codes unless its an american market vehicle

these vehicles are known for ignition coil failure. typical symptoms include: Misfire, power loss, vibrating engine, poor fuel consumption. If the vehicle's engine vibrates, it be misfiring. Is your chk engine light on???

thats a feature on a car so you dont over rev the engine

transmission shift solenoid can cause it feels like engine is bog down

The engine has a rev limiter to keep from blowing engine up with too much rpms at idle.