Clear the codes if you can - rip the ecu out - remove memcal - get some dielectric / silicone grease from Repco (not cheap) Supercheap also has it but only in sachets - this will promote a connection & also insulate - do a search on it - makes connections easy to pull apart - stops corrosion buildup. These computer systems work on low voltages so any connection problems will cause dramas & give you fault codes. If any boots are shot on connections you can buy replacement connections or if you cant you can go to an electrical wholesaler (240v) & buy some 3M rubber splicing tape - if you stretch it - it creates heat & vulcanizes itself together - it is the best thing next to replacing the boot. Unlike electrical tape it will stay there.
Go through your EFI system (better doing the whole car if you intend to keep it) & pull things apart & push back together each connector several times to knock off any corrosion (you probably wont be able to see it) & pump the grease in - you can put it in with light bulbs to stop rusting in / you can put it on your ignition leads to stop leakage & water affecting your engine. A lot of problems - especially intermittent ones are caused by poor connections. When I first did my EFI courses years ago I was introduced to these products & never looked back - I have used it on vending machines (currently have this business) in washing machines (used to have a laundromat) & of course on cars & it has improved the reliability factor by a huge margin in all cases.
I have cured heaps of problems this way - I am not saying that this will fix your problem in this case - but it will eliminate potential problems in the future & it might just get rid of some of those codes .....
http://www.permatex.com/products/au...e/auto_Permatex_Dielectric_Tune-Up_Grease.htm
3M Products | 3M Scotch 23 Rubber Tape | Adhesives, Abrasives
Not sure if this link has the right one but most wholesalers have it its just 3m scotch rubber splicing tape - self vulcanizing... neither of these products are cheap - but they are worth their weight in Gold.
Clean your battery terminals & clean the earth connections on the engine block - there is one major earth under the DFI module at the front & one at the back of the engine - plug the memcal & ecu back in & go through the relearn procedure which as far as I know means letting it idle in & out of gear (if auto) with ac on or off - go for short drive up to 80 k & slow down to a stop & do the idle thing again - it should be ok from there - one other thing to do is listen to the throttle body & see if you can hear some air whistling inside - lift the air cleaner lid up & put your ear up to it see if this changes with the idle speed - rev it up a bit & it should drop back with giving it a rev & come back in on letting the throttle go - good idea to pull throttle body off & clean - use carb cleaner in the throttle body & keep it away from the TPS - check to see that the throttle is not closing completely - the screw adjustment is just used as a stop only to stop the throttle plate from wearing into the housing. Air flow meter would have the biggest impact here on idle - I would imagine -
Once you have done this recheck your codes - get back to me & I will see what I can do - its a lot of work but it will help a lot - I would also go as far as checking your ignition leads & or replacing them - if you loosen the lead at the coil - you can pull it out to give it a bit of gap & see how good the spark is - use insulated pliers - if not plastic ones - try not to let it run with sparks going all over the place as it can causes the coils & DFI module problems - so have someone ready to turn the key off. The spark should be good enough to jump an inch or even more - any less than this & the coil probably needs replacing.
The other thing you can do is check for fuel flow & the easiest way to do this is take the return line off & put the hose into a bottle - if the pump is ok it should flow about a liter a minute. This will tell you that the pump has enough flow & enough pressure. That's about all I can help you with at this stage ...Good luck
