250 Momentary missfire

Discussion in 'Mechanical - Engine, Gearbox, Exhaust etc' started by RSrob, Jul 18, 2017.

  1. On cold start up the car seems to missfire or flatspot when trying to accelerate, this only happens for a few seconds then all is ok..the engine seems to rev drop rev drop slightly too at the same time. Its tricky to explain. The miss/flat has only started since it was decatted and mapped.. any ideas?
     
  2. Have you had any problems with it dying out on starting at all as it could be some thing as simple as the air temperature sensor which gives similar symptoms especially first thing in the morning. quite common and under a tenner to fix
     
  3. Need to leave it to tickover longer & don't touch the throttle for a minute. Mine did it, revs up & down stuttering. Think it's just one of their many charms.
     
  4. No nothing like that..just the stutter
     
  5. Majority of renault sports are abit funny driving straight from cold. Wouldnt worry about it.
     
    Jimbob 2705 and RSrob like this.
  6. Ok thanks ill see how that goes
     
  7. f4r's have always been a bit agricultural from cold, bit lumpy etc. They're a bit sensitive to plugs, so if they've never been changed it might be worth it.
     
  8. I found mine ran alot smoother with new plugs gapped from the standard 0.9 down to 0.6.
     
  9. My car is doing the same thing, I'd like to think that most if not all sensors are fooked I have to literally hit start 3 times in the morning before it decides to fire up

    NB! Car was mapped and decat a few years ago

    Sent from my P1000 using Tapatalk
     
  10. Mine does it (275). Looked into it and it seems the F4R is just a grump bitch when cold.

    Runs better on Vpower but still not 100%
     

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