2003 1.8ltr holden astra runs rough

[Lizzie]

My astra runs rough on cold starts, only been doing this since I had new timing chain and water pump installed, also needed new o2 sensor. Also spark plugs and service and throttle body clean.Now when cold she runs rough, wants to stall, slight backfire, revs up and down until warm, then run like a dream, until cold again. What could be the cause of this, I've taken the car back three times now.
Cheers Lizzie :-/

[guy 27]

possibly timing out, incorrect plugs, egr valve, bad fuel..... list goes on.

Any lights on the dash?
can you please do a pedal test (have a browse on here for how to do it) and report back if any fault codes come up.

Without the above information its going to be extremely hard to give an answer on what the issue may be.

[Lizzie]

No error codes but possible vacuum leak? And has only run rough in morning or cold start since having timing belt, o2 sensor and plugs done, they now say possible MAF problem. I feel it's not tuned right so have to leave car overnight for them to do cold start. I've always maintained car and never had her running rough. Am very frustrated and seem to keep paying out with no result.

[guy 27]

have they put the maf in the right way? there is an arrow on it for airflow direction.
if it was a vacuum leak you should be able to hear it.
You shouldn't be paying for them to not resolve the issue.

[Lizzie]

I think they are getting a new MAF sensor to see if that's the problem and I guess if it is that will cost more, I'm still sure it's a timing issue as she has a slight miss, are there a specific type of spark plugs for her.. She's a 1.8ltr, I'm not sure what type they used.
Cheers Lizzie :-)

[chris_r]

I'd say check the timing belt. If it's one or two teeth out, it will run like a bag of crap. They probably didn't rotate the engine a couple of times after setting the tension to check that the timing marks are still aligned properly. I've done this by mistake before and it does sound a lot like the same symptoms.

[Lizzie]

Thanks to everyone who gave me advise, turned out to be the MAF installed a new one and now my baby purrs like a kitten. Very happy. By the way I've been told to switch to premium fuel, the astra has always been run on unleaded so is it a good idea to switch to premium? If so how would I do it, do I let her run low then fuel up with premium, or not?
Thanks x

[JohnBu]

Good news!

Just fill her up full with premium the next time you need petrol.

It's been 10 years, it's not suddenly urgent.

I'd run a full tank of premium once for every 3 tanks of regular.

But if you notice it runs better or more economical, then use premium all the time.



Sent from my iPhone 4S using Tapatalk

[Lizzie]

Thanks johnbu,
I'll give premium a go next time I fill up.
Cheers Lizzie xx