So I have recently changed the Idle Air Controller, Coolant Temperature Sensor, Spark Plugs, Rotor and cap. The CTS was in regard to this latest problem which did not help.

Symptoms: When starting cold the Engine runs very rough at idle sputtering and will die if I don't give it gas. When I rev it the miss goes away until it is warmed to ~120F indicated on my dash then it runs OK.

PS: Checked the fuse to the cold start injector and it was good. Fuel pressure ~43 psi.

Does anyone have any ideas what could be wrong?

  • What's the model, year and engine?
    – GdD
    Nov 13, 2019 at 15:48
  • It has electronic fuel injection and i an 86 corvette 350 with aluminum heads.
    – 3dalliance
    Nov 13, 2019 at 16:09

1 Answer 1


I would check the Cold start injector, Thermo time switch and the fuse. If any of these has failed you will not have the rich mixture the engine needs when it is cold.

After that I would check the fuel pressure to see if the fuel pump is failing.

rical diagram

  • Thanks, That would make sense. It does have a cold start injector ... I'll check the fuse and the injector which may be shorted.
    – 3dalliance
    Nov 14, 2019 at 17:10
  • @3dalliance check the edit I did to this answer, there is one more part involved for the cold start system.
    – Moab
    Nov 15, 2019 at 15:57

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