My 99 vw cabrio has problem starting it has new batt,new alt, new starter the only way it starts if I put starting fluid on air flow

gets expensive just guessin' and replacing parts- this is an old car and it sounds like you have fuel system problems, after all- you are now into a restoration job-

Try adding some seafoam fuel injector cleaner to gas tank and use the middle or high test gas that is if you use the low grade gas all the time. Also would not hurt to change fuel filter if have not done so in a while.

vw and audi cars have been nitorious for being high tes only cars. If you been using regualr every day gas its probly got the car all gummed up with carbon. Start by checking your plugs and crank case breather hoses and clean the maf and check the throtal body for carbon deposits.