Dismiss Notice

Welcome To CK5!

Registering is free and easy! Hope to see you on the forums soon.

Score a FREE t-shirt and membership sticker when you sign up for a Premium Membership and choose the recurring plan.

Runs Like Crap When Warm?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Rocky91, Sep 29, 2002.

  1. Rocky91

    Rocky91 Registered Member

    Joined:
    Feb 14, 2001
    Posts:
    44
    Likes Received:
    0
    Location:
    Rochester, NY
    When my Blazer gets up to operating temperature the idle speed drops by about 300 rpm and becomes very irractic. It will stall out while at cruising speed and the SES light will come on but does not set a code. I'm leaning towards it being a plugged catalytic converter, but was wondering what you guys think it could be?
     
  2. wrathORC

    wrathORC 1/2 ton status

    Joined:
    Apr 27, 2002
    Posts:
    908
    Likes Received:
    0
    Location:
    Hancock, MI
    When was the last time you replaced your ignition coil?
     
  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

    Joined:
    Feb 17, 2000
    Posts:
    7,385
    Likes Received:
    0
    Location:
    Atlanta
    If it's running ok when cold then it might be time for a O2sensor. Yours is old enough that the computer has no real checks on the O2 unless it just can't see it at all. The recomended replacement interval is 60k. Check the EGR also it might be screwed up and sticking open.
     
  4. Rocky91

    Rocky91 Registered Member

    Joined:
    Feb 14, 2001
    Posts:
    44
    Likes Received:
    0
    Location:
    Rochester, NY
    I checked the coil with an ohm-meter and it seems to be good, but I will switch in one I took off a camaro to make sure. I changed the O2 sensor last week, along with the TPS sensor and the IAC sensor. I also checked the EGR and it seems to move okay.
     
  5. Thunder

    Thunder 3/4 ton status

    Joined:
    Jul 20, 2000
    Posts:
    8,946
    Likes Received:
    1
    Location:
    Northeast Nevada
    If the SES light comes on but no codes are set check the distributor module before replacing anything else. Sounds like a bad module to me.
     
  6. 4x4Freak

    4x4Freak 1/2 ton status

    Joined:
    Apr 21, 2002
    Posts:
    792
    Likes Received:
    0
    Location:
    Lubbock, TX
    Check your coolant level. If it is low the temp. sensor wont read correctly. The water will pass by it and then stop, making the computer think the engine is cold then hot, etc. This will cause the idle to speed up and slow down. It doesnt do it until the engine is warmed up because the thermostat is closed not letting the coolant through.

    We had this happen when my brother swapped a TBI 350 into his truck. We put enough coolant in the radiator and it stopped doing it.

    This may not be your problem, but its definitely something to check.
     
  7. supersize75

    supersize75 1/2 ton status

    Joined:
    Sep 27, 2002
    Posts:
    2,638
    Likes Received:
    0
    Location:
    gilbert az......by Phoenix
    I just delt with a f*rd junko and I REPLACED THE;COIL,BATTERY WIRES,CAT-CONVERTER,WATER PUMP, RADIATOR,PLUGS, CAP, ROTOR CAP .......FINALLY GOT CURRIOS ABOUT THE FACT THAT IT RAN THEN AFTER 20 MIN DIED AND DIDN'T WANT TO RESTART SO I PUT A HEAT LAMP BY THE DISTRIBITER CAP BEFORE RUNNING IT AND IT WOULDN'T START ...THE TIMING AND POINTS WERE WAY OFF SO I JUST REPLACED THE DISTRIBUTER ...PROBLEM SOLVED I HOPE THIS HELPS CAUSE I WAS CRAZY FOR A FEW MONTHS BUT NOW THAT I FIXED MY G/F TRUCK SHE LOVES ME AGAIN.

    SHAWN
     

Share This Page