I have a 89 corvette with probally a fuel problem. I had day chevrolet replace the fuel injectors and filters and drove the car 500 miles which it ran fine. I then stored the car in the garage for a month. When I took the car out it had the same hesitation problem then had trouble starting. I notice that there was alot of carbon buildup in the tail pipe. Any information will be helpful.

You have wasted a lot of money buying stuff that is not needed.
Check the pulses from the crank shaft sensor.

Check your fuel pressure it should be 40-47 with the key and engine off and 30-44 with engine running.If its not within these specs then replace the fuel pump and filter.

Sounds like you have spark but no injector pulse. This can be from the throttle position sensor showing that the throttle is wide open, which shuts off the fuel to clear a flood situation. The easy way to check this is unplug it. If the car starts its the sensor. There are 2 wires on the injector. One is key on battery voltage the other goes to the ecm. You can buy a light called a noid light to plug into the injector plug and it should flash if you have injector pulse. If no pulse check ignition module in the distributor. If not that re-post and we can go from there. Have a nice day and good luck!

change fuel filter

check the fuel injectors - seems the new fuel is messing these up...

yea if that don't work replace fuel pump and clean injectors

The 5.0L injector is sized to deliver approximately 4.05 milligrams of fuel with a 2.5 millisecond pulse or 18.13 lbs per hr at approximately 36 PSI. The 5.7L injector is sized to deliver approximately 4.83 milligrams of fuel with a 2.5 millisecond pulse or 23.92 lbs per hr at approximately 43.5 PSI. This information is typical for all manufacturers and flow rates will vary slightly even between identicle injectors.
Good luck and hope this helps.

I also have an 89 corvette that had the same problems.Ill tell you what fixed my problem. I also changed the fuel pressure regulator(its under the plentum in front of the distributor)This was not the problem but I replaced it anyway. The problem with the idle was my injectors.The factory multecs that are in there were original to the car and are not compatible with the blends of gasoline that are sold at most stations.Too much ethanol. I replaced mine with a set from fuel injector connection.(FIC) They are rebuilt with a three year warranty. Thats better than new ones. They are bosch 3.The car has run perfect every since.As far as the long starts it helped that too but if you do a little research on the 89 corvette youll find that GM put some crazy software in the computer that year. It requires the engine to turn over two times or about 3 seconds before the injectors fire.Thanks and good [email protected]

replace the coolant temp sensor, not the coolant temp sending unit

i had almost the same problem i changed my fuel pump and fuel filter and it worked u mite try that first.