I guess it depends on how many kms your car has done and and what % change in fuel burn are you worried about.
On a low kms car any degradation in fuel consumption is likely to be one or more items from a bunch of other factors I'd be investigating first. If you are running a self-tuned program, check your fuel settings and timing. Even check for binding brakes, including handbrake, and tyre pressures. You might clean your MAF and look at your air-filter and check your plugs, although the plugs in these cars last for eons. Even ask yourself if your driving habits have changed significantly.
The last thing I'd be stressing over is taking off the manifold or pulling injectors (which are in the head, not the manifold) until all other avenues have been exhausted (pun slightly intended).
My fuel burn hasn't changed in 65,000km and remains good; it's never been "decarbed" by any process, physical or chemical, and I don't drive like a granny, even though (regrettably) the car spends too much time in the city.
Look for the simplest solutions first, not the most complex that involve time, effort and money and which, unless you have a lot of experience, are likely to cock up and incur even more costs.
As an aside, and this isn't directed at anyone in particular but from what I read here a lot of the time, I reckon the biggest problem half these cars suffer from is meddling owners long on enthusiasm but short on experience.
Last edited by Doug_MPS6; 20-01-2012 at 11:31 AM.
CP_e Standback & PNP; CP_e 3" SS Downpipe; Corksport FMIC with Top-mount K&N filter & OEM Ram CAI; Turbosmart BOV; Dashhawk; Prosport Boost Guage; JBR solid shift bushes; DBA 4000 Wiper-Slot front rotors; Hawk Ferro-Carbon HPS Street front brake pads (@ 69,000km); Sumitomo HTRZIII's in 225/45 x 18