Forums Forums Enthusiast Forums A - Z Autowirral Someone to look at rough running car

My Yaris Verso (with 170k miles on!) has suddenly started running like a dog and idling very slowly. Any recommendations please for someone to look at it, preferably tomorrow. (It's barely drivable but I can get it recovered somewhere)

Are there any lights on the dash? Have you tried unplugging the mass air flow?

Engine management light's been on for years with car running ok! Confusingly the problem started the other night when the card died at traffic lights. Breakdown guy found no output from alternator and flat battery. Recovered home and recovered again to auto electrician, both recovery drivers commented on how rough it was running when they loaded it. Went to pick it up from auto electrician today (was slipping belt, not alternator) and it was running like a dog, so had it recovered back home again! Auto electrician reckons it must be coincidence that slipping belt and whatever else is happening happened at the same time. I'm now wondering if low battery could have caused a problem with a nearly failing fuel pump?? (I'm no mechanic!)



No. Can a MAF fail suddenly?

Technically anything can fail suddenly. Where abouts is the car? It could be a number of things. Is it petrol or diesel?

Oxton Village. Petrol.

I've just been out and disconnected the MAF. Idle speed was higher when I first started it but fell back again quickly. I drove around the block a couple of times and it certainly drives better with it disconnected (air temperature's dropped of course since I tried it a few hours ago if that makes any difference). Does that mean the MAF's at fault? Is it ok to drive with it disconnected as a temporary measure?

I should have said before - auto electrician checked for error codes and found none.

Okay fair enough. So the MAF is a definite possibility. Driving around with it unconnected shouldn't do any major damage but you will see an increase in fuel use etc so it's worth getting it sorted if it is that.

Chances are if the MIL light has been on for a while the issue could be related to that and whatever it is has actually been breaking down and has been reported by that light. As for the auto electric guy not finding any codes again that's worrying as there must be codes for the MIL light to be on. I'm happy to pop my diag equipment on to see what it says and see if we can get to the root of the issue if you'd like.

Cheers, that would be great if you could. Whereabouts are you, or are you mobile?

To be quite honest, I'm not quite sure what the electrician checked, it was done as a favour when he was in the middle of locking up. Some years back I did the paperclip in the socket and count the flashes trick and as far as I remember there were two non-specific codes (or maybe one). I've just checked my ebay records and I bought a MAF for it a bit over four years ago to see if it would clear the light (it didn't). From the price I paid it wasn't an OEM part, don't know if that makes a difference?

Managed to find the original MAF that I removed four years ago and stuck it back in. Now running much better though maybe not quite 100% (or what passes for 100% on a car this age). Then noticed that the o-ring on the one I took out had broken and was hanging off, so took the refitted one out to check and it doesn't have an o-ring at all! New o-ring now on order at Johnson's...

It might take a while to learn a new MAF, air leak on the engine side of the MAF will certainly mess things up.

Take battery off for a few minutes.