To worry or not to worry? Engine Management light flashing!

[Cal]

So today I took the car to the garage to have the manifold and cat fitted to replace the old manifold and a very bodged decat job, I picked it up lovely everything was great drove home sounded amazing with it on. I go to edge out in traffic close to my house and the engine management light starts flashing i give it a few revs and it stops then I'm driving down a duel carriage way cruising and it comes on so i give it some revs and speed up and its stop when i pulled in by my house it came on again luckily for me i had a OBD machine in my car only a cheap eBay one but one nonetheless I plugged it in it gave the faults 'multiple cylinder mis-fire' After some research i found many people had this problem with the light and few people have said this is what theres was diagnosed


At one point the revs did drop and i had little power to move but i drove it around for a bit to see if any other codes came up and nothing has and now it seems to be driving fine. Do i worry about this? I'm wondering because of the new manifold been fitted and such the car might not be used to it or when he was fitting it the lambda sensor may be damaged or blocked? I did ring the guy and he said let me know how it goes and if it continues to drop it back into him but i've read about 10-15 post and they all have different things that solve it from blocked injectors to a wire under the passenger seat which funnily enough is where i stored my diagnostics and it did only come on after i put the machine back under there?

I know this is very long but thanks for reading!

 

[Yiannis197]

Don't worry about it mate. What fuel do you use?

 

[Mattb_197]

Just clear the codes and keep an eye on it. Intermittent faults are a pig to trace down as you can't replicate them easily.

If it starts doing it all the time then you know you have a problem, it might just be the car getting used to the different gasses and flow after having a de-cat on for so long. You could check the wires under the passenger seat to see if you've knocked anything but I don't have a clue what you'd be looking for as I've not heard that one before myself.

All you can do is clear all the codes and then take it on a good run, I'd be tempted to give it an old Italian tune up and see if it happens again.

 

[Cal]

I use Shell V Power but i've only filled the tank once and £30 another time since owning it so can't vouch for previous owner and I'll try give that a go but not a lot of way round me to do it but suppose that gives me good cause to take it out for a proper driver somewhere nice eh?

 

[Mattb_197]

If it was stood for a while before you bought it then it could well be the car clearing its throat if you will. V-Power and other similar high performance fuels also contain a lot more cleaning additives than your regular unleaded, so it can be like putting a bottle of fuel cleaner in over a few tanks of it. Just keep an eye on it and see how you get on after your blast.