Christina Aguilera style dirty backfiring after about 10 mins of driving.

I struggle to build revs when it happens
Can hardly drive it
my tacho needle becomes erradic at the same time but more so the big loud backfiring!

What could it be....

throw ideas peoples... cuz im outta companys 2 look at my car.......literally.

what has been checked.

sounds like your getting to much un bunt fuel

pretty much everything ignition wise.

Timing is 100%
Leads are 10mm Top Gun Race Series, about 6 months old.
Spark plugs are new
Dizzy is new
Cap is spanking new
Coil been load tested and all that, 100%.

Basically, runs great for a bit, then idle changes, then go to take off, cars missing then as soon as I get going just BANG BANG BANG kinda thing, might clear up for a bit, just depends, has its good days and bad, but like I said, weirdest thing is the tacho needle becomes erradic as well?

Have they swapped the ECU over with an identical one with the same tune on it?
Anything really to check fuel wise? hmmmm..

Any chance my fuel reg is cutting in and out?

Next option is just to sit it on the dyno

Advantages of a full aftermarket ECU. :) Chuck it on, make it play up and let the ECU tell us whats going on!

sounds like what i got. put mine on dyno and found it was running lean, so they suggest i got a fuel problem, but where noone knows lol

sounds like what i got. put mine on dyno and found it was running lean, so they suggest i got a fuel problem, but where noone knows lol
Isnt that there job to find out why its lean.
Ben - Why not grab another FPR from the wreckers off another 4 banger and swap it over qiuckly, wont cost you a cent

I run a malpassi Rising rate, would love to upgrade to a turbosmart 1:1 seeing as my engine is pre-mapped, no real need for a rising rate, ecu only gonna let a certain ammount of fuel in at certain rpm.

But will give it a go.... errm...unless someone donates one for me, turbo smart only 400 bucks:P