help!!

[ace-135]

1986 T-Type WH-1 pkg. 47,500 miles...stock except for 6 position chip and air intake. Was running super until 3 weeks ago and started to stumble on acceleration. It's been at 2 different shops and i'm out 500.00 plus!!! It's still not right. I've replaced the following: coil, TPS, mass air flow, fuel pump, o2 sensor, fuel pump hot wire kit(thanks to cottons) and now they say it's 90% but not quite right!!!! Once it warms up they say it okay but still some hesitation when it's first run. All numbers look good ...fuel air mix, volts, fuel pressure, etc... any suggestions? It's a stab in the dark but hey....what can I loose now ...another week without the car??!!