Hesitancy and popping on hard acceleration..

[AlfaJack]

Today whilst out I was giving it some stick in 2nd gear, as the power was coming in nicely and at about 3500 to 4000rpm I felt a hesitancy, it is like a couple of small jolts and at the same time there is a popping/snapping noise - it sounds like it is coming from the exhaust as in unburnt fuel igniting....not 100% on that though.

I tried gunning it a few more times and it kept doing to same, I am reluctant to keep my foot in as I dont want to do too much damage.

Any ideas what it is?

Couple of things to note...I have a Squadra chip and I am running it on RON95 fuel....worse still, it has a tank of Supermarket (Sainsburys to be precise) fuel in...is this of any significance - never used supermarket fuel before)

Thanks
Jack

[wrinx]

When were your plugs last changed? Q4s seem to be very sensitive to worn or unsuitable plugs.

What about your plug leads?

wrinx

[AlfaJack]

Plugs have seen quite a few miles now - perhaps 12K. Plug leads looked ok when I took it all apart to paint the inlet - guess they could be breaking down inside though....

[sub555]

id say plugs like wrinx says mine did the same thing matey with worn plugs

[cuore_sportivo_155]

i'd check the plugs first too

[Steve Webb]

What they said. Sounds like plugs to me.

[wrinx]

Plugs have seen quite a few miles now - perhaps 12K.

Shouldn't they be changed every 12k...no iridium platinum coated kryptonite 60k jobbies here

wrinx

[AlfaJack]

Thanks guys. I am going to get these nice Colder plugs NGK B8EGV.

[wrinx]

There were some reasonably priced one on ebay recently...let us know your source.

wrinx

[AlfaJack]

Ordered from here for ?27.75 delivered. Will let you know if it solves the problem in a few days.

[AlfaJack]

Sorry, left out the link in the above post:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=260319460955

Have not got them yet....but driving the car tonight it seems like there is nothing wrong

Even had a nice rare oversteer moment on a little roundabout.
It was very cold and slippery though

[wrinx]

Same price I found...let us know how you get on as I'm after some too

wrinx

[wrinx]

Have they arrived yet....fitted....has it sorted the car?

wrinx

[AlfaJack]

It hasnt done it again. I have the plugs but not fitted them yet, not planning to unless the problem comes back...bit confused as to why its like this...

[Evodelta]

Because it's Italian.

[wrinx]

It hasnt done it again. I have the plugs but not fitted them yet, not planning to unless the problem comes back...bit confused as to why its like this...

But if you've covered 12k since the last lot were fitted...they're due anyway.

wrinx

[AlfaJack]

But if you've covered 12k since the last lot were fitted...they're due anyway.

wrinx

Its a guess at the mo, need to check and write up the history...job for the weekend

[wrinx]

wrinx

[AlfaJack]

4.5 years of history, receipts (lots)and MOTs to estimate the mileage, a normal person would have entered the history in a book as it goes

[AlfaJack]

Because it's Italian.

AKA S.H.I.T - Self Healing Italian Technology

[WhizzMan]

Well, running it on 95 with a squadra chip is sort of asking for spark timing retardation by the ECU (knock detected with knock sensor, retard spark a few degrees). In cooler weather you're less likely to have knocking, so that might be why it's not happening again. Good spark helps since you're more likely to burn your mixture properly and fast enough so it doesn't get a chance to knock.

[AlfaJack]

It was hesitating quite a lot today so I fitted the new plugs. It is pulling well now - I wont say this is a fix until iv driven it a fair few more times yet as it was an intermittent problem. All is well for now and the back end is sliding round nicely in this icy weather

[mverhari]

I had the same problem ,I fitted the colder ngk plugs and the problem was solved

[AlfaJack]

I had the same problem ,I fitted the colder ngk plugs and the problem was solved

Glad to hear it. Seems pretty common with this engine.