Car runs poorly when warm

[Simone2607]

Could someone help me with this, I got the car recently and on the journey home I started to notice the rev counter dropping right down and then shooting back up. The next day whilst going to work it started to stall in traffic, the car will start again but takes a while. It is also very jumpy when accelerating, especially in second gear. I've kept and eye on it since and noticed that these problems only start when the engine temperature gets past 75 degrees. I can prevent the car from stalling if I keep pressing on the gas every now and then.

I've recently serviced it so changed all the filters as I thought it could have been a fuel/air problem. I've taken it to the mechanic and got it back after 30 minutes as he said he was 100% sure it was the coil pack, so I replaced it and replaced the spark plugs but no difference, the leads looked in good condition so haven't replaced them. The last thing to add is that I'm getting terrible fuel consumption, last week I got 70 miles with £20, all town driving so a lot of traffic but it shouldn't go that quick?!

Things I thought it could be, MAF sensor, Temperature coolant sensor or speed sensor (these are all things I found off other posts that were related to mine, but none were exactly the same)

Car is a Golf MK4 1.6 petrol

Any thoughts?!

[theshrew]

I think if its the same problem it's a common fault on the GTI. If I remember correctly it was the air temp sensor that goes. Might be a different engine to yours though.

Get it plugged into a diagnostic machine that will tell you for sure. It will probably be something simple

[Simone2607]

Yeah that's just part of the MAF so could be just what i thought. But wouldn't engine light be on? I'm taking my car to the mechanic tomorrow morning so are there any tests i should do tonight to try and figure it out. I'll take the MAF out and clean it, lets see if that makes a difference

[theshrew]

No not part of the MAF its a seperate one i think.

Did you get sorted ?

[Steve H]

The common temp fault is the coolant temp sensor, doesn't always put the light on.

[Simone2607]

Thanks for your help everyone, I took it to the mechanics and the bill came to £204. The camshaft position sensor and the MAF needed replacing. The camshaft position sensor is quite a common problem with the symptoms I was having so I'm surprised I found nothing online that pointed towards that. Hope this helps other people. If anyone was having the same problem I'd recommend just buying the parts and changing them yourself, they are both very easy to do, I was well over charged. Could have don't the job myself for under £100

[andyiley]

VERY common fault with exactly the same symptoms on Corsa C.