Hi there guys. Yesterday when driving to work my car started to misfire badly under load. when accelerating, especially between 2000 rpm and 3000rpm it starts to kangaroo almost like a petrol car with the choke out.

my landrover sprung a leak in the fuel tank, so i put the fuel i managed to save into the audi. this diesel had some red in it and i kind of thought it might just be the poor quality fuel. however i used all that fuel and it was refilled with premium stuff.

This morning going into work the car was virtually undriveable. I went to overtake a very slow driver (30mph on open road) Floored the throttle in 2nd gear pulled out to overtake and the misfiring was so bad i couldnt overtake the car. the car is misfiring in all gears, although most noticeable in 3rd, probably because thats the gears used most often for acceleration on the windy country roads where i live (highland scotland) I used to be able to overtake easily in 5th gear just by putting the foot down, but am now struggling to maintain speed on the slightest gradients. every time i put my foot down the misfire comes in and the car starts jumping around.

I have checked all the vac hoses and they all seem to be ok. I haven't had a chance to check the turbo bearings yet, but will do thast when i get home. the other thing i'm suspecting is the MAF sensor. Ive pulled it out, but dont have security torx bits to get the sensor out of the housing to have a good look, but the gauze screen seems pretty dirty so cleaning the sensor with alcohol might do the trick.

any suggestions? I should be getting a shot of a vagcom lead tomorrow, but ive never tested the software i downloaded so no idea if it will work or not.

edit: meant to say, its a 1997 a4 1.9Tdi quattro, with 250'000 miles (not a typo)

cheers guys

 

I would start by replaceing the fuel filter & see what happens.

 

I'll be doing that anyway to get rid of any traces of red diesel, but wont be able to get one until next week probaby unfortunately. would seem strange to me that it would start doing this suddenly though if it was just a dirty filter.

I'm now back home and it was much better on the way home. still hesitant and lumpy but not nearly to the extent that it was this morning and yesterday.

the mornings here are still pretty cold (about freezing this morning and a degree or two below yesterday) I wonder if that might have something to do with it?

Ive just realised looking at this site, that it seems youre all from the states. In case you dont know, red diesel is diesel that has a much lower duty on it and is for farmers etc to run tractors on and is very much illegal to use on the road. It has a red dye in it so that it can be identified when you're stopped at the side of the road and your tank gets dipped by the authorities. My landrover only gets used around the farm here at the moment and as such had some in the tank when it sprung a leak. as there wasnt much in it i just stuck it in the audi rather than chuck it away. even at the lower duty rate its still about 65 pence per litre (diesel from a garage (gas station lol) is about £1.50 per litre (about £7 a gallon (imperial) or $11.16 a gallon) at the moment and rising a couple of pence a month

 

Hi again. I pulled the turbo off and had a look at it. The bearings and what I could see of the turbine and impeller blades all look/feel ok. It spins freely without any roughness although the inlet side seemed a bit oily but I think that's fairly normal so I can rule out the turbo.

The other thing I did was blank off the egr. I put a clanking plate between the flex pipe and the valve and the valve and the inlet manifold. Is there something else I should do for this? I tried a search but just got loads of posts about keys and radios.

I took the car for a quick run and it went perfectly so I'm hoping that was the problem. I'll see how it goes tomorrow morning.

Any further thoughts?

 

Did the fuel filter get replaced yet?
The fuel was probably dirty & caused your fuel filter to clog up. Replace the filter & see what happens then!

 

Hi again, I haven't changed the filter yet as I cant get one until Tuesday. I will be changing it though. The fuel that went in was dirty but i ran it through a coffee filter afterit leaked out the landrover to make sure it was clean before it went into the car. I will be changing the filter anyway though.

Ran the car into work and back today (about 30 miles total) with no further problems. That's with the EGR blanked off.

I've got a vagcom lead now so will plug it in as soon as I've got the program on the small laptop (assuming the downloaded program works) and hopefully get some ideas. There are a couple of other issues I need to look at anyway like the brake pedal buzzes when braking below 10mph, obviously a bad sensor/exciter ring on one or more wheels.