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Tintop problem
speedyxjs - 21/1/09 at 06:27 PM

I really cant figure this one out.
The car in questions is a 98 Vx Astra Estate 1.6 8v. The problem i that it 'stutters'. Its fine accelerating to the required speed but when you back off the accelerator to just have enough throttle to keep the car at the speed, it stutters. It does it for all speeds although seems to be a little worse at 40/50 mph but that could just be me.
My initial thoughts were idle valve but cleaned that. I then considered a sticky valve or dodgy fuel injector but have emptied a tank of fuel with injection system cleaner and the problem is no better.
Then this morning i considered the head gasket as there is alot of 'mayo' on the filler cap but had previously put that down to condensation as until i got the car, it had done about 1800 miles per year, but dismissed that as it doesnt seem to be using any water.
Does anyone else have any idea's?

MikeR - 21/1/09 at 06:33 PM

what is the oil dipstick like?

I was going to suggest stuck / bunged up EGR valve. it sounds similar.

Might also be worth checking the TPS.

I had a 1.8 which did something similar at tick over due to the EGR valve and associated pipe work being bunged up. I also got to the point of losing a cylinder when hot due to the ECU having a bad track inside it.

stevebubs - 21/1/09 at 06:37 PM

Plugs / Leads / EDIS?

britishtrident - 21/1/09 at 06:59 PM

Reading the pending fault codes or even better the live data might give a clue as to what is going on.

However EGR valves are a known problem on Vauxhalls and your symptoms might just about fit

The only real cure seems to be blank the valve which can generate a fault code that has to be disabled in software.
(I think Tech2 will do if you have access to laptop this see
http://www.arcadiaincar.com/ for Tech2)
Without more info it could be anything from the thermostat stuck open to the coil pack & plugs or the primary lambda sensor.

I think the tps is less likely because they only tend to fail at the very bottom end of the scale ie below 10% to 20 % throttle.

speedyxjs - 21/1/09 at 07:00 PM

quote:
Originally posted by MikeR
what is the oil dipstick like?


Looks fine. No mayo on it. The car had a full service before i got it a few month back so plugs etc should be fine.
Stevebubs - Wouldn't the leads do it all the time? EDIS?

dinosaurjuice - 21/1/09 at 07:27 PM

is there a second switch on the brake pedal?

if so, check it with a multimeter to make sure its opening/closing properly.

iank - 21/1/09 at 07:38 PM

Sounds like the EGR, I went through 2 in 4 years on the same engine and the brother in-law went through 3 on his 16v over a similar period.

Exactly the same symptom, drives along fine then stutters and is then fine again for a while. Gets gradually worse over the weeks and months.

Mine also produced mayo on the oil filler, but it didn't seem to use any water so I just cleaned it off and carried on. If there's mayo in the water that would be a bad thing.

speedyxjs - 21/1/09 at 08:07 PM

Just done a quick google on EGR valve and it sounds like that could be it. How do i go about blocking it off?

Danozeman - 21/1/09 at 08:23 PM

EGR valve, also more simpler air leaks in the inlet. a cracked/split inlet hose will do this. Vauxhalls dont like it. That will give you jerkyness when u back off to come to a junction aswell.