Alfa Romeo Repair: Alfa 147 1.6 Impulso, throttle position sensor, alfa 147

Question
Hi, I recently bought an Alfa 147. After two days I noticed that above circa 80km/hr there is a slight feeling that power is reduced or lost for a split second( it is an almost imperceptible feeling) i.e. as if you take your foot off the accelerator BUT I neither speed up nor slow down. It happens a lot, every 3-5 seconds and not at consistent intervals or speeds. The Alfa garage said the fault was with the injection system and have replaced the relevant parts. Unfortunately the problem persists. Any ideas?
Michael

Answer
It is always a good idea to confirm the diagnosis before doing the replacement. You might have water in the fuel.  This can be checked by replacing the fuel filter and adding one pint of rubbing (isopropyl) alcohol per 10 gallons of fuel and seeing if the symptom disappears over a couple of days. Otherwise you have a lean miss caused by a faulty throttle position sensor or a faulty map sensor or a faulty mas sensor. Testing is required. Or, after trying the alcohol trick try unplugging and reconnecting the above mentioned sensor connectors.