earlier today i was going to drop the mrs off at her parents.

so i come to a roundabout, slow down and take it in second. going straight ahead and the road breaks into two lanes, so i give it some boot (70mph road) in second and got like this pop hesitant surge around 5000-5500revs. changed upto third straight away and it didnt do it again.

its done it a couple of time, always in second around those revs. almost seemed like a backfire i dunno got me stumped. car drives fine now and has done previously when this has happened.

my99 uk classic. standard apart from dump valve/nur spec-r decat.

any advice

 

Maybe your hitting the fuel cut
You got a boost guage?

 

yes possable fuel cut due to overboost, this is an issue that occurs when de- catting. a remap should cure it

 

but it doesnt feel like hitting a brick wall. also the first time it did it at around 5-5.5k revs i hit the redline no probs in second. no limp mode etc...

 

Plugs maybe need changing but for now whip em out and regap them to 0.6 that might fix it.

 

Mine did the same every now and again. I was running higher boost than standard. It happened only on the motorway and only if it was floored in 5th, but as said not always, once in a blue moon. A map tweak sorted it.

 

went round the chris's house (flix) earlier on. he had a look at the coil pack and noticed the clips were loose. tightened them up a little. gonna check tomorrow for hairline cracks/look for sparks etc.

as for the plugs, i have no idea what to do with that andy.

 

Can be a pain to do if your not the spannering type. Get someone to take them out and regap to 0.6mm or fit new and gap those to 0.6mm. What might be happening is when the boost comes in it's blowing the spark out due to the larger than normal gap the spark has to jump. My mate had his STI servised and it was doing the same thing. I removed the new plugs gapped them and it was fine after that.

Could be something else but you need to start somewhere

 

hmm after chris cleaned one of the coilpack end plugs, hasnt done it since.

also, the car had a major service when the new gearbox was built and fitted, so i assume jase @ scoobybits fitted new plugs.