'98 Blazer; rough running until fully warmed up

coachhillcoachhill Member Posts: 13
My '98 with 95k miles has developed a real annoying habit. When the outside air is cold, she starts and runs like a champ. When it gets above say 40 degrees F, she stumbles and balks and misfires until she is fully warmed up. It runs a little better at full throttle, but that's not convenient around town. Numerous check engine codes have indicated "intermittent misfire", nothing specific.
I have replaced the air and coolant temperature sensors/sending units and have maintained plugs, wires, filters, etc. The problem is definitely temperature related. Is there a possibility the fuel pressure regulator can be the problem? I'm thinking the unit may expand and shrink with temperature changes. Just a thought.
Please help if you can!

Comments

  • marblazemarblaze Member Posts: 16
    SOUNDS LIKE MINE SAME THING UNTIL WARMED UP COMPLETELY THEN SHE RUNS FINE WELL AFTER RESEARCH GM HAS DEFECTIVE INTAKE MANIFOLD GASKETS MADE OF PLASTIC THEY LET FLUID SEEP INTO CYLINDERS AFTER ENGINE COOLS DOWN AND THEREFORE IT ALSO LEEKS IN UNTIL ENGINE WARMS UP AND RESEALS, I REPLACED MINE 2 WEEKS AGO BEEN FINE EVERSINCE
  • marblazemarblaze Member Posts: 16
    my blazer has a bad clicking noise when moving , i can put it in 4x4 the noise stops any ideas as to what might be the issue??
  • vornskyrvornskyr Member Posts: 1
    I have the same issue rough running until engine is warm!! now its not even starting did you have any luck coachhill? did you try replacing the intake manifolds? just troubleshooting here.
  • coachhillcoachhill Member Posts: 13
    That was a long time ago, but as best I can recall a really complete tune up fixed the issues. Plugs, plug wires, distrib cap, fuel and air filters, etc. I found a bad plug wire and that was probably the main cause. I didn't change the injectors but that's a good next step if the tune up doesn't work.
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