172 kangaroo misfire GURUS please help!

[roadrunner_182]

My 172 recently developed a fault, initially occurred accelerating in third gear it appeared to misfire then recover. The problem gradually got worse to the point of struggling to drive it and eventually it died and I towed it to the garage.

The garage replaced the plugs and leads and coil, told me the car was fine, I travelled 100metres and problem was still there so returned to garage. It's not showing any fault codes, no lights on the dash or anything. An auto electrician has checked it no electrical issues cam sensor etc all ok.

I asked if it could be injectors apparently you can only check pulse rate or something but injectors also fine. When driving the car you can see the rev counter go erratically up and down from say 3k to 1k as it kangaroos. The garage told me they've just put engine cleaner in it to try that. I'm at a loss currently £300 out of pocket and problem remains.

The car is mint fsh only 40k miles any gurus out there got any ideas? I hear Fred is the man in the know so Fred if you read this Any input would be appreciated.

Thanks

 

[Cookson]

so you've paid them for the work, but they havent fixed the problem?

 

[roadrunner_182]

Yup piss take isn't it, I'm not happy, just trying to figure the fault as they are useless.

 

[roadrunner_182]

Just been out in it again, much improved but still misfiring in 3rd no errors on dash no errors stored on ecu???

 

[Cookson]

Is it only doing it under load? Not just when you rev it at a standstill?

 

[roadrunner_182]

Yes only when accelerating fine standing still :-/

 

[Cookson]

Fuel pump perhaps?

Loose cam sensor?

 

[roadrunner_182]

All sensors appear ok apparently. Fuel pump has been mentioned but at this rate I'm gonna be replacing parts at big cost as they don't seem to have a clue what's up with it! already spent £344 :-/

 

[Cookson]

Have a word with Birchdown? They arent too far from you, may be able to have a quick look for you for a few quid

 

[roadrunner_182]

Cheers pal will do

 

[gazwold]

I have just had the same fault this week was fine at idle but under it misfired quite a lot turned out to be the pre cat lamba sensor

 

[roadrunner_182]

its really bizarre, since they replaced the coil plugs and leads its definitely improved but still coughs and misfires?! They plugged their universal fault reader into the car and everything showes ok, spoke to Birchdown on the phone they thought possible oxygen sensors all sensors and injectors show ok apparently. Going to a different garage this week renault -tech who have proper renault diagnostics so hopefully get it sorted there, birchdown just a little too far and i cant trust my car to get me there :-/ really not happy at the whole experience £340 worse off and still got a problem with misfiring!

On another note apparently m cat has a rattle internally so thatll be another £100+ quid and im guessing its not related!

 

[jinjur]

I was under the impression that the Lambdas dont actually throw codes until they have melted and been recycled into sovereign rings so in terms of your problem, there is only a handful of things that could be responsible........and you have replaced the top of the bunch, next stop.....try a Lambda.

p.s. I have one I pulled from my car to replace with a brand new one, after which, I realised that mine actually wasnt broken.

You can have it for £10 on your door if you want?

J