mysterious starting problem

[stevanom]

Hi, mi 1987 MA70 (no turbo) 3.0 6 cillinder has always started in 2 seconds. Even after five years of inactivity it stated in 2 seconds. NOw I have used it intensely, but quietly for a number of months (while waiting for new company car). I had timing belt, spark plugs and orioginal exhaust system replaced at maintenance in a Toyota garage. About five thousnad kilometers later it began to start worse. It gets worse and worse and now I have to try two to three times for several seconds. When it finally runs it turns smoothly, but stutters during about 5 kilometers when driving. After that for the rest of the day it runs and starts like as usual : like clockwork.
oil consumption not even half a liter in 15.000 kilometers
water level steady
temperature steady as ever
kilometers 205.000
Anyone any ideas? I am getting desperate
Thanks already
Steven