Kia Shuma - slight hesitation at low revs

[oldcars]

The old bus has developed an issue. Handy as the 75 is in the bodyshop and i am taking the Shuma to the NEC sat/sun!

 

Its just been serviced by my mate and the other day developed a slight hesitation at low revs. The only code that pops is is that of an O2 sensor but its been replaced years ago and the code pops up every few weeks. 

 

Any ideas on what to check first?

[scaryoldcortina]

plugs and leads first.

[oldcars]

Cheers, plugs replaced at service not sure of leads. Will find out.

[Stanky]

Our Rio started like this then got worse and worse, eventually bogging down horribly below about 3000rpm (I guess, it was an 'L' so had no rev counter) and was diagnosed to the MAF. This was on the Mazda B-series 1.3 SOHC engine though, so probably different to yours. Disconnecting it made things no better though.

 

Start cheap - carb cleaner down the throttle body and over the MAF gubbinz to clear off any grot?

[oldcars]

Thanks, it's a 1600 but i its a mazda b series engine as well so this could be it. Did the carb clearer do the trick for yours?

[Stanky]

It did help, but only for a few weeks, then began to get worse again. This could be because of grot getting through the air filter or poor seating causing air to get in after the filter but before the MAF or a combination of the above. It certainly helped, but I think the long-term fix was a new MAF for it. I bought a pattern one but didn't have a lot of luck with it and as a new one was £400 I opted to sell the car to someone else before things degenerated further.

 

cleaning the sensor bit of the MAF (its a resistor which sticks out in the air flow and presumably senses by the cooling effect of the air flowing over it. You might be able to do a maplin's fix but I am not very good with electrics) is easier with the MAF removed, but can be done with it in situ if you use a torch to see down the barrel as you blast it with carb cleaner.

 

I have the new MAF still, it had to be wobbed up with bathroom sealant as the sensor stuff wasn't glued to the barrel very well, but it should still work. its yours for free if you want to try it? I can't guarantee it will either fit or work, but its going on the shitecycle thread. The part number is OK32A13210. Yours for the cost of postage.

 

PM me if interested.

[oldcars]

Thanks mate, good of you. Let me have a look at cleaning it first and i will let you know.

[Craig the Princess]

Did it do this straight after the service? Dodgy new lead sometimes happens or loose connection would be my first check.

[twosmoke300]

Manifold airleak of some description . Prob why it throws an o2 code . Check vac pipes etc

[lisbon_road]

Manifold air leak is definitely first try.  It is has an airflow sensor, that is a good bet.  Some you disconnect and the hesitation or poor idle goes away and they are just generally anaemic.  Whether that works with yours or not I don't know.

[oldcars]

Did it do this straight after the service? Dodgy new lead sometimes happens or loose connection would be my first check.

Not straight away after about a week.

[oldcars]

Thanks, stuff to check when the weather improves its grim.