Intermittant Misfire At Idle

[sy300]

Just today my Stagea has developed an intermittant miss when at idle.

It only seems to be present under 1000rpm. The wagon also seems to be using noticeably more fuel.

I'm thinking it's a coilpack, but I did drive it a distance with the low fuel light on and it started after that. Maybe it sucked some crap up from the bottom of the tank.

Could it be a partially blocked injector? Would that explain the higher than normal fuel consumption?

Also, wouldn't a stuffed coilpack cause a miss all through the rev range?

Anyone had similar and can help?

[Ska]

I dunno, personally I have had a blocked fuel filter because of gunk and it didnt cause a miss. Never heard of an injector being blocked, but sounds plausable, SK?

If the coil pack was tottally dead then it wouldnt be firing at all, but if it was intermittantly firing then it would get worse as the rpm gets higher, wouldnt it?

But either way I couldnt see any of the above affecting fuel economy that much..............?

[justin911]

ya my car does the same thing.. pretty sure its using more petrol 2

I was told the missing is because my plugs are at 6.x mm or something like that.

She's fine when you drive though, doesnt miss at all..

I had a look at my coilpacks last night, they looked pretty good.. not that i no what im realy looking for though

[Laylon]

I did have a similar problem with misfiring but my engine stalling and it stuggled to drive at all most times. It ended up being the Air flow meter in my case. It seems to be running well now that I have replaced it. I am about to take it for a drive to Coffs Harbour next week so I should find out if there are any gremlins left.

[BoyWhoCriedWolf]

Gap the plugs to 8mm. Coilpacks are a common problem. They are usually fine down low and start to struggle up high. I dont if the reverse is possible.

Its one of those how long is a piece of string problems. Get it on the dyno!

[LoNg_ShaNks]

I had a look at my coilpacks last night, they looked pretty good.. not that i no what im realy looking for though

im wid ya brutha

Hey but atleast we try

[wa nick]

I had exactly the same problem a small intermittant miss at idle, it slowly got worse. It ended up being a stuffed coil pack, $70 later good as gold.

Cheers Nick

[AlexCim]

Gap the plugs to 0.8mm. Coilpacks are a common problem. They are usually fine down low and start to struggle up high. I dont if the reverse is possible.

Its one of those how long is a piece of string problems. Get it on the dyno!

[BoyWhoCriedWolf]

Drunk? It was early afternoon after all!

[sy300]

Thanks for the advice.

When I get back from my work 'holiday' to the US I'm getting the wagon serviced, so I'll get them to check it out.

If it is anything major, my mechanical insurance should cover it.

[fcruz3r]

darnit...my wagon started to develop the same missfire at idle...driving seems fine...think its bad but my safc is doing some correction...raised the boost to 10psi and gave it a good revving ....missfire seemed to have dissappeared for now....it started after a normal cruise to canning vale via tonkin n roe....temp outside was quite warm so i dont know if its temp related.

hope its something easy to fix like plugs...or worst case air flow sensor and not a stuffed valve

[sy300]

Finally got the whole problem sorted.

After the burnt valves got replaced, it still had a slight (but less dramtic) misfire. The mechanic could not replicate it, so I took him for a drive. The miss also came in under high rpm/load. I nailed the car, and sure enough at about 4500, it started missing and felt like it hit the rev limiter.

They took the coil packs out and got them tested, all 6 were f%^&ed. Replaced them all, car runs sweet as.

On talking to the mechanic, it turns out that my engine was overboosting because of a stuck wastegate. This caused it to be a bit lean (as well as the stuffed injectors) and burnt the valves. This hid the other fault of the coilpacks.