1993 Astro running rich

1993 Astro just had a tune-up, new coolant sensor, distributor cap, rotor, plugs, wires, coil. Runs fine when cold after warms up runs rich, sputters loses power above 40mph. After sputtering for a while it runs fine then starts all over. SES light not on. NOt showing anything stored in computer. 186k

She's great if I can get her to stay running!

I have the same problem you are reporting 93 astro 100,000 miles can't figure it out myself, is your c.p.i. ?

1993 Astro just had a tune-up, new coolant sensor, distributor cap, rotor, plugs, wires, coil. Runs fine when cold after warms up runs rich, sputters loses power above 40mph. After sputtering for a while it runs fine then starts all over. SES light not on. NOt showing anything stored in computer. 186k

She's great if I can get her to stay running!

idle speed control valve wont throw codes if the mechanical part is bad. codes some from the vaccuum (electric) portion only