A bit of a misfire between 2-3K rpm

Ive noticed I have a bit of a missfire when I hold the car between 2-3K rpm when I rev the engine up with no load ie when in sat in neutral.
It dosent miss at all when Im driving just when there is no load on the engine, I have also noticed the odd miss on idle and my idle sometimes sits high, like 1500 rpm but every now and then it will settle down to just over 1k rpm but not very often, it usually sits high at about 1400 rpm

Any ideas what this could be? I'm not sure if the high idle is related to the missfire at all but I thought it would be worth mentioning incase the two are connected

Have you checked the i.a.s  and checked the base timing  at all ?

No I have not mate, were and what is the IAS?

And how do I check the base timing mate?

http://www.gtir-motorsport-club.com/t2701-high-idle-probs
have a little read through this bit  few things to check there to begin with fella ...

Cheers mate I'll try that idle adjustment screw tomorrow and see if I can get the idle to settle down a bit and see if that clears up the missfire

It could be a multitude of things on the misfire  last time you did a service plugs .leads .dizzy cap .rotor arm.  maf . For the idle screw there is a pic of it in useful diagrams bud ....

Thanks mate, I've found the diagram of the idle adjustment screw so I'll have a play and try and get this idle down a bit.

I thought the missfire could be a multitude of things. I recently tried cleaning my MAF sensor, don't know if that really did anything and my plugs are fairly new, about 500 miles tops on them.
I suppose it's just a process of elimination.

I get a bit paranoid when things are not 100% but I would sooner try and get it 100% than ignore small problems to the point they become one big problem lol

Cheers for the advice matey

There's probably a few things I can try swapping round off my spare engine because it has the full intake plenum etc still attached to it

What plugs and leads are you running ? .... when you cleaned the maf  how did you do it .... what about fuel filter also ?

I would take plugs out and give them a clean, are you running bcr8es plugs? If its a slight misfire now it may develop to abigger miss soon

I'm running ngk bcr8es plugs and stock leads. I'm going to try swapping the leads over from my other engine and I'll give the plugs a clean, or just swap them as I've got four new ones sat here.

When I cleaned the MAF I took it it appart and used electronic contact cleaner and cotton wool to gently remove any crap from the two elements.

I will try the fuel filter also, I'll get a new one ordered and see if that helps at all, can't hurt to replace it anyway.

By the way I had the missfire before I cleaned the MAF

I have just tried quickly swapping the leads and I thought it had made an improvement at first but it's still got a bit of a missfire.

I have noticed my AFR gauge reading high at idle, it sits around the high 14's low 15's and I have noticed it quickly spike into the mid 15's everytime it misses on idle.

I have just took it for a little drive and my AFR gauge does seem to be reading a little lean, especially when I let it tick over after driving, it's sometimes sitting as high as 16 but a blip of the throttle seem to help bring it back down.

I'm going to get a Fuel filter ordered, is there anything I can do to test if it's possibly the fuel pump on its way out?
I'm also thinking perhaps my MAF is playing up but I'm just guessing at the moment
My AFR's defiantly seem lean but every now and then when cruising with little load I have seen it occasionally go really rich and sometimes stays rich on idle and again a blip of the throttle sometimes brings it back normal into the 14's

Perhaps a faulty injector?

Hardy172cup wrote:Thanks mate, I've found the diagram of the idle adjustment screw so I'll have a play and try and get this idle down a bit.

I thought the missfire could be a multitude of things. I recently tried cleaning my MAF sensor, don't know if that really did anything and my plugs are fairly new, about 500 miles tops on them.
I suppose it's just a process of elimination.

I get a bit paranoid when things are not 100% but I would sooner try and get it 100% than ignore small problems to the point they become one big problem lol

Cheers for the advice matey

how was your fueling after cleaning the maf? sometimes they run lean after being cleaned, mine did, mine has a similar problem and there was a few boost leaks when it got checked over, mine still does it occasionally when all the leaks were fixed except the dumpvalve which i havent changed yet

I did notice it ran slightly leaner after cleaning the MAF and to be honest I wouldn't be surprised if I have few boost or vac leaks, I'll have to get it checked over. Im also going to try removing the BOV I just need to find something to plug the BOV hole up with

also check all the little vacuum ports and pipes from plenum
if its leaning out on afr's then sounds like either a boost or vacuum leak unlikely to be an injector

just check dizzy cap too and make sure ignition system is in tip top condition but this sounds like an air leak somewhere to me

What should I look for when I check dizzy cap bob? I've never took one appart before lol.

Im thinking I've got an air leak somewhere, it seems the most probable scenario.
I could do with one of those smoking device things to check for leaks in the system, would make life easier lol

I've got some new silicone hose for the vacuumed pipes bill if ya want to change it just pop round and I'll give you it. Can't hurt to swap it anyway and when I did mine the tick over dropped to a reasonable level

Cheers Darren, I have changed a few of the vac hoses already but I think I might aswell just change the lot and b done with it, The only problem is how I'm going to remove and reattach the hoses from the little vac box at the back of the plenum   

Ye I've not done them lol

You could alway swap some bits off mine ie afm etc

Cheers mate that's decent of you, I'm going to have another look around tomorrow and see if I can figure out what's a miss, I need to try removing the BOV, unless you have a stock recirc valve I could try?

I'm sure there's a few things I could probably try swapping over to see if it cures the issue

I'm out Saturday mate but in every evening in the week except Thursday, that's maypole night lol

Lol I forgot you were one of the maypole dwellers I'll have to remember if I ever drive past on Thursday night I'll have to give it some and try and disturb the peace a bit  

If you dont mind having a look at it with me mate I'll just bring it up whenevers going to be best for you mate, I don't want to come up too late in the evening though because my exhaust is LOUD and it would be noisy for the neighbours if it's a bit late and we keep starting it and revving it to 2-3k rpm every 2 minuets