Have to hit starter 2-3 times, sometimes more before car starts - have replaced fuel pump, fuel filter, throttle control unit and idle sensor - has not cured problem - however, when unit warmed up, it will start first crack ???? what are we missing ????

This is complex to diagnose. Here are possibilities:

Here are some possible causes and solutions:

Fuel pump relay: A faulty fuel pump relay can cause the fuel pump to stop working intermittently, which can cause the engine to stall. You can check the fuel pump relay by swapping it with another relay of the same type in the fuse box. If the problem goes away, then the relay was the issue. If not, then you can move on to the next possible cause.

Clogged fuel filter: A clogged fuel filter can restrict the flow of fuel to the engine, which can cause the engine to stall. You can check the fuel filter by removing it and blowing air through it. If there is no resistance, then the filter is not clogged. If there is resistance, then you should replace the filter.

Vacuum leak: A vacuum leak can cause the engine to run lean, which can cause the engine to stall. You can check for vacuum leaks by spraying carburetor cleaner around the intake manifold, throttle body, and vacuum lines while the engine is running. If the engine RPMs increase, then there is a vacuum leak.

Faulty idle air control valve: A faulty idle air control valve can cause the engine to stall at idle. You can check the idle air control valve by removing it and cleaning it with carburetor cleaner. If the problem persists, then you should replace the valve.

Faulty throttle position sensor: A faulty throttle position sensor can cause the engine to stall when the throttle is opened. You can check the throttle position sensor by using a multimeter to measure the resistance across the sensor terminals. If the resistance is not within the specified range, then you should replace the sensor.

Faulty mass airflow sensor: A faulty mass airflow sensor can cause the engine to stall when the throttle is opened. You mentioned that you already changed the MAF, but it's possible that the new MAF is also faulty. You can check the MAF by using a multimeter to measure the voltage across the sensor terminals while the engine is running. If the voltage is not within the specified range, then you should replace the sensor.

Faulty ignition coil: A faulty ignition coil can cause the engine to stall when it gets hot. You can check the ignition coil by using a multimeter to measure the resistance across the coil terminals. If the resistance is not within the specified range, then you should replace the coil.

Possibly the throttle position sensor. Or maybe you are having a problem with the fuel injectors. I would have the fuel pressure checked for proper pressure-that's the point of replacing the pump: proper pressure is critical for good driveability. Replacement pumps, particularly aftermarket, can sometimes not perform adequately.

Yea , those crossfire injection vettes can be a bear sometimes . I had dealings with them 84-85 - 86 working as a tech at a chevy dealer . Don't remember much about them , haven't heard anything about them for long time .

How's the fuel pressure ? Have you put a fuel gauge on it ? I would imagine you don't have a Tech 1 scan tool ? What's the map sensor voltage at idle ?

1984 Corvette hesitation stalling stumbling During Warm Up Only

1984 Corvette cleaning checking the check valves

turn key on and start car,let it die and check for fuel pressure ,find fuel line and remove cap that looks like valve stem for tire,press neddle un derneth ,probly have no fuel,if so repace fuel filter and pump.try to spray brake cleane in throttle body after it dies if it will run on brake kleen you have no fuel,replace pump and filter.

It should have an idle air control valve which lets air into the intake to control the idle speed. The valve could be faulty, or dirty, or the throttle body could be dirty. The computer opens and closes the valve to regulate idle speed.

Throttle Position Sensor?
Idle control motor?

Check throttle position sensor (TPS) is a sensor used to monitor the position of the throttle. The sensor is usually a potentiometer, and therefore provides a variable resistance dependent upon the position of the valve. The sensor signal is used by the engine control unit (ECU) as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position. For example, in fuel injected engines, in order to avoid stalling, extra fuel may be injected if the throttle is opened rapidly (mimicking the accelerator pump of carburetor systems). the cost about 50-75 bucks.

I have a 90 chevy k1500 350 tbi with same problem! I have traced problem to... after turning on key fuel pump kicks on when u crank it over injectors shoot gas and truck starts! After few seconds injectors stop spraying and truck dies! This can happen many times over and over! Eventually sometimes truck stays running and all is great! I changed ignition module, oil pressure sending unit (which i was told controls gas after vehicle is running) fuel filter, computer, fuel pump relay, I am at a loss now! Hope this helps and hope someone can help me!

1 Inspect M.A.P. Sensor Faulty M.A.P. Sensor. 2 Inspect EGR Valve Improperly Functioning or Faulty EGR Valve. 3 Inspect Fuel Injector Dirty or Worn Fuel Injectors. 4 Inspect Idle Air Control Valve Damaged, Loose, or Faulty Idle Air Control Valve. 5 Inspect Idle Speed Actuator Damaged, Loose, or Faulty Idle Speed Actuator. 6 Inspect Throttle Position Sensor Faulty or Incorrectly Connected Throttle Position Sensor. 7 Inspect Fuel Filter Clogged or Dirty Fuel Filter. 8 Inspect PCV Valve Plugged or Damaged PCV Valve. 9 Inspect Carburetor Worn, Faulty or Damaged Carburetor. 10 Inspect Valve Burned, Worn, or Sticking Exhaust Valves. 12 Inspect TimingSet Slipped TimingChain or Worn TimingGear(s). 13 Inspect Fuel Pump Faulty Fuel Pump. 14 Inspect Camshaft Camshaft Lobes Worn. 16 Inspect Point Set Burned, Worn or Incorrectly Set Ignition Points.

There is an Idle control sensor that has likely gone bad, take it to a trusted mechanic or dealer and have them replace it to solve the problem--roughly $300 repair at a Toyota dealer