Ecotech Developed a miss that I can't fix... Help needed

[Tsunamix]

So the blue bomber has developed a miss.

I have replaced plugs leads, coil packs and DFI. checked the connections on the TPS, MAF, CAS, CPS and all the injector connectors. Degreased the engine throughly to make sure there is no shorts.

Run wynns injector cleaner through, and while I was at it drained and flushed the cooling system.

Reset the engine computer, checked the firing order and leads again, and I'm still stumped....

Interestingly -
It's usually a single misfire not a batch of missfires
It happens more at idle or under light loads than under heavy loads.
The longer you drive for, the less it occurs, so that after 20 minutes or so it doesn't occur at all.

My thoughts - could I have a bung injector otr some sort of transient fuel blockage ?

This problem was occurring a week ago, and I have steadily changed out parts in the hop of fixing it. The miss was much worse at one point, but does not seem to be related to one specific part.

It's an erratic inconsistent miss.

It's not throwing up any fault codes, and I can't think of where to go next.

Any suggestions or advice would be really really helpful.

Cheers Blokes and Ladies.

 

[Tsunamix]

Had a good look at the Purge Hose, Purge valve and connections. Everything seems in place. Did find a heat aged & crackerd hose between the the TB and intake manifold =- the short 8" Vent Hose I think it's called. Ill replace that, might help

 

[BackyardSpecial]

Try removing the injectors and checking if they are indvidually blocked.There is a small basket filter in the back of each injector and it is common to find them full af sediment.
Also check you're fuel filter.

 

[ripty]

Just a thought,

Try a wet and dry compression test, cold and hot. Checking for a dodgey valve.

 

[Tsunamix]

Compression is 155 KPA +/- 5 kpa in all 6.

Replaced a heat aged vent hose, did a full top end de-carbon with the 3Bond stuff, checked the purge hose and purge valve.

I will look at the injectors tonight, currently hoping it's just a bit of water in the fuel, a bit of metho in the mix will absorb and burn that.

Starting to pull my hair out now.

 

[Tsunamix]

More and more confusion.

ECU is not throwing up any error codes.

It happens most when cold, at idle and just off idle, I've had it stall on me about 10 times now at idle. After 20 minutes or so running it stops happening totally (or so close to totally that I can't tell the difference). Have reset the ECU, changed fuel, thrown some metho in (about a litre when filling the tank ) and no change.

I haven't changed the injectors - run out of money to spend for a month and I'm not sure of the value in just hand cleaning them when I can replace them for $120.

I'm at a loss here...

 

[acarmody]

Sound a bit like my car, she idles OKish, but when slowing down it will really drop revs and sounds like she will stall before revving up to bring it back, and can hesitate when taking off sometimes. I've had injectors professionally cleaned, new fuel reg, new fuel filter, blocked EGR pipe, new ignition leads, swapped ignition coils and plate with parents one, and tried IAC and TPS, still damn well doing it.

 

[Tsunamix]

After running for 15-20 minutes, the hesitation & miss fire dissappears..
I keep trying things, still no luck. Will clean the injector baskets on the weekend, im considering flushing the fuel lines incase theres some crap floating loose in there.

I dunno...

 

[Tsunamix]

Injector baskets cleaned, fuel rail blown clear and flushed, fuel pressure regulator replaced, fuel filter replaced, fuel tank emptied and cleaned, IAC gasket replaced (no vac leak), all vac hoses replaced, gaskets inbetween upper plenum and spacer added, gaskets between lower plenum and spacer replaced, PCV valve cleaned and checked.

1 mechanic bamboozled. 1 Auto sparky bamboozled. Still not showing any error codes.

)*&'n dirty ^(*)^ rotten _&( sh^t P((S F***K C**n* of a car.