Ahhh! Idle!!!

[MARK A]

The saga continues:S The car has stopped doing the funny rev jump thing that it did on the rubbish petrol I was using but I can't help noticing that the idle is really lumpy and rough. The needle sits at just below 1K but it's just rubbish! It's jumpy and chuggy! I have a sports cat and sports exhaust but I wouldn't have thought that make any difference! The car drives fine and has had new leads and coil-pack a few weeks ago! I know my old 182 was a bit lumpy but nowhere near this bad! Any suggestions?????

 

[bigmonmulgrew]

Check your engine mounts

 

[MARK A]

Will this make it idle wierd then?? What's the best way of checking this??

 

[MARK A]

It seems to be more of a 'chugging' from the exhaust gasses! Surely this can't be the mounts?:S

 

[bigmonmulgrew]

Mine used to shake on idle. Called the aa out for another prob and he noticed the mount at rear underside was loose. Check they're tight.

 

[AmirClio]

Sounds like a vacuum hose to me, not sure if 172's have map sensors but it could be that.

 

[timboss]

my car used to be very lumpy and that you can hear is chugging away at idle , feel in in the floor and the gear stick and i needed to do was to change the spark plugs and it was fine and dandy!!!
honest i just changed it a few days ago!!!

sorry for my "and's" i only got a E in english !!

 

[MARK A]

I'm quite technically minded but don't work on cars that often, sorry guys!! How can I check the hoses and the mounts?

 

[mini-valver]

Just get a socket on all the engine mount bolts and check there tight. Is the exhaust blowing as youve only just had one fitted IIRC. Could be leaking abit, have a feel around all the joints.

 

[MARK A]

Will do!! I'll pop it back to the place that fitted the exhaust for me if it's blowing, they'll be cool I'm sure! I'll pop a socket on the engine mounts first though

 

[MARK A]

Right, the plot thickens!!! I started the car up this morning and stood outside it to see if it was still idling funny. It started up and idled fine, but a few seconds later I heard a noise which sounded like a switch tuning on, then the idle went a bit funny again! I popped my head under the bonnett and the fan was on!! WTF! It was -3 on the temp sensor! I drove 10 miles to work and the fan was still on! This is deffo a problem but I wonder if it's doing something to the idle at the same time, either that or the idle problem is making the fan come on!!!

 

[S22 JGS]

you got ure air con turned on mate?
172 idle and air con dont mix LOL

 

[MARK A]

Yeh, the air-con was on!!! That's why the fan way kicking in!! Doh!!! It still has a funny lumpy idle though ): I just does a funny jumpy thing! I think it's running a bit rich! Think the Lamda is first port of call!

 

[MARK A]

She went into the garage yesterday to have a trained eye look at the the idle problem. Prior to booking it in I bought a new lamda and a new set of plugs just incase this was the problem. At about 12ish I recieved a phone call say that all was normal. In their opinion the idle was fine, it wasn't hunting, wasn't cutting out and the emmissions and lamda's were all cool! I questioned this as in my opinion the idle wasn't quite right but they said that it's fine and all is well. I said that if they wanted to try the new plugs to see if it made things any better than I was cool with this, I'd pay for the work to be done. They said that there really wasn't any point fitting expensive plugs when the old ones had only done 20Kish of their 60K plus lifespan and were working fine. There was only one fault code that came up on the computer and that was to do with the 'throttle postion sensor'. They erased the code and said to come back if the I had further problems! I use the garage regularly and they're pretty good, I'm just in two minds now as to weather to pursue the problem, or write it off as normal. Maybe I'm being too picky!