I am no expert but what about the booster?

Iggy

PS I see that you changed the booster, are you sure it was correctly installed? What about a vacuum leak somewhere along the lines that causes the booster to fail a little or have problems?

Another thought - have you checked the hoses? Maybe one of the hoses has a bubble. When you pump the brakes it expands therefore causing the spongy feeling?

__________________
Insanity: doing the same thing over and over again and expecting different results.

2006 - Suzuki Gran Vitara (2.0 L fully equipped) Like this car so far except for trying to put on the seatbelt.
1988 - 190e - 2.3L - 172K miles (It now belongs to the exwife)
1999 - Chevy Blazer LS Fully Equiped - killed it June 2006
2001 - Honda Civic EX - 68K miles (sold June 2004)
1963 - 220S - Dual Carb 6 cyl. (sold)
1994 - Yamaha WaveRaider (fun to ride)