MikesTractor
New Member
NEED HELP. Very annoying problem. Not just any common misfire.
I started having misfires when I bought the car 8 months ago.
The misfire happened when the car reached 30mph and above. Like any good samaritan with a 2nd hand car without maintenance history, I changed spark plugs which cured the problem.
A couple months go by and problem re-introduces itself. Needing a car service anyways, I took the car to a local garage and asked if they could change spark plugs again and make the missfire go away. They said it was cylinder 2 and 4. The missfire went away but only for 10 Miles! They recommended I change coil packs next, which I did, but that didn't cure the problem at all. Thinking it could be a fuel problem I aslo poured injector cleaner in the tank but it only started misfiring worse.
I was fed up chasing the issue myself as I needed a functioning car for work, so took it to an Audi garage. They performed a £204 full diagnostics and here is what they found out:
Missfire on Cylinder 2 and 4, swapped sparkplugs to 1 and 3, now missfire on 1 and 3. So, easy fix, they blamed the "non genuine Audi" spark plugs and put in new Audi ones. The problem was gone and they performed a full drive test which went successfully. I got the car back and this time after 250 miles I started having misfirings again??
I just started a week of work and needed the car so, I couldn't bring it in (luckily I mostly commuted in 20mph zones so it barely missfired). When I topped up the car with fuel mid-week I decided to fill it up with e5 Super 98 as a small attempt to help fix it. To my surpise after about 50 miles of driving with 98 in my car, the missfiring went away completely! It ran great, but it only made me more confused what the problem was. HOWEVER, I'm now 300 miles further, my tank is half full still with the super 98, and I'm having misfiring again. It's not a constant misfiring cylinder, its sporadic; going up hills, or when accelerating over 30 mph.
I've yet to do a cylinder pressure test myself as I'm not sure Audi did it. I'm inclined to just replace the sparkplugs again with expensive ones but it's just asking for the problem to come back; if it goes away at all. Not sure what to do! Anyone who knows more about engines could have an idea what could cause these symptoms?? Could it be burnt valves? Bad injectors? electric fault? clueless.
From previous threads with similar issues, here are some common questions. My car doesn't have Cylinder on Demand. turbo got looked at recently by Audi regarding a sensor fault so, unlikely its a boost issue. Car has 114k miles. Old but definitely not hopeless
On a side note, just in case it might be related, my coolant runs out quite frequently and have to top it up. I checked the engine oil cap and there's no fouled oil (garage also didn't notice bad oil when I took it in for service), nor am I getting white smoke out of the exhaust. Pipes seem ok and never have a puddle under my car after standing still for long time.
I'd love to rely on my car for work and travel without filling the boot up with coolant and sparkplugs. Thanks in advance
Mike
I started having misfires when I bought the car 8 months ago.
The misfire happened when the car reached 30mph and above. Like any good samaritan with a 2nd hand car without maintenance history, I changed spark plugs which cured the problem.
A couple months go by and problem re-introduces itself. Needing a car service anyways, I took the car to a local garage and asked if they could change spark plugs again and make the missfire go away. They said it was cylinder 2 and 4. The missfire went away but only for 10 Miles! They recommended I change coil packs next, which I did, but that didn't cure the problem at all. Thinking it could be a fuel problem I aslo poured injector cleaner in the tank but it only started misfiring worse.
I was fed up chasing the issue myself as I needed a functioning car for work, so took it to an Audi garage. They performed a £204 full diagnostics and here is what they found out:
Missfire on Cylinder 2 and 4, swapped sparkplugs to 1 and 3, now missfire on 1 and 3. So, easy fix, they blamed the "non genuine Audi" spark plugs and put in new Audi ones. The problem was gone and they performed a full drive test which went successfully. I got the car back and this time after 250 miles I started having misfirings again??
I just started a week of work and needed the car so, I couldn't bring it in (luckily I mostly commuted in 20mph zones so it barely missfired). When I topped up the car with fuel mid-week I decided to fill it up with e5 Super 98 as a small attempt to help fix it. To my surpise after about 50 miles of driving with 98 in my car, the missfiring went away completely! It ran great, but it only made me more confused what the problem was. HOWEVER, I'm now 300 miles further, my tank is half full still with the super 98, and I'm having misfiring again. It's not a constant misfiring cylinder, its sporadic; going up hills, or when accelerating over 30 mph.
I've yet to do a cylinder pressure test myself as I'm not sure Audi did it. I'm inclined to just replace the sparkplugs again with expensive ones but it's just asking for the problem to come back; if it goes away at all. Not sure what to do! Anyone who knows more about engines could have an idea what could cause these symptoms?? Could it be burnt valves? Bad injectors? electric fault? clueless.
From previous threads with similar issues, here are some common questions. My car doesn't have Cylinder on Demand. turbo got looked at recently by Audi regarding a sensor fault so, unlikely its a boost issue. Car has 114k miles. Old but definitely not hopeless
On a side note, just in case it might be related, my coolant runs out quite frequently and have to top it up. I checked the engine oil cap and there's no fouled oil (garage also didn't notice bad oil when I took it in for service), nor am I getting white smoke out of the exhaust. Pipes seem ok and never have a puddle under my car after standing still for long time.
I'd love to rely on my car for work and travel without filling the boot up with coolant and sparkplugs. Thanks in advance
Mike