Oldsmobile Cutlass Ciera poor idle

Tiny
CA441970
  • MEMBER
  • OLDSMOBILE
I have a 1993 Oldsmobile Cutlass Ciera S sedan with a 3.3L and 109111 miles. I have an issue with the idle. I have replaced the wires, put Bosch platinum +4 plugs in, and replaced the 3 coil packs. I also replaced all of the vacuum hoses I could find. I just bought a fuel injection pressure tester, and I plan on checking the pressure tomorrow. It runs fine when accelerating, there is no hesitation. At cruising speed you can feel a little miss mostly 45-60MPH. Idle though has a very obvious miss or a loping to it, it does this when it's cold or warm. It feels sometimes as if the idle gets too low and then the IAC kicks it up a bit. Is it a bad IAC, TPS, Mass airflow sensor possibly? I have no codes showing up at all. I also bought a can of cleaner for the mass airflow sensor, specifically for delicate electronics. I plan on doing that tomorrow too.

I have a strong mechanical aptitude for car repair, I went to a technical college for suspension, brake, and minor engine repair, but never made it through the ignition/fuel/emissions control part as the school closed down in the middle of my schooling.

Any help will be appreciated.
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Tuesday, February 20th, 2007 AT 9:19 PM

5 Replies

Tiny
KIN CHAN
  • MEMBER
This sounds likes it need a li'lo thinking. Let see
okay.I think u can save buying the tester. Cuz if u have a fuel vol. Or pressure issue.U'll definitely have a problem on acceleration. Cruise speed minor missing. Chk O2 sensor. Chk voltage on signal wire. Snap throttle should be around 850-900 mv high and induce vac should be around 100 mv. Hold engine spd around 2000 rpm. Ushould be able to see about 1 hertz of high low switching.
Now. Let see if u have a vac leak. Place a vacuum gage at idle.U should get like 18 inches of vac or more. Needle should be steady. If it wander. Thats a good indication of vac leak. That probably cause a lean misfire while idling and runs better when rpm move up. Cuz ur vac drop and move toward atmospheric pressure. Make sense.U sounds mechanical auto incline. So. Send me a msg if above test didn't nail the cause of ur problem
later man
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Tuesday, February 20th, 2007 AT 10:32 PM
Tiny
CA441970
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Hello, well I checked theO2 sensor last night, it's within specs. I put my vacuum tester on, and I got 18-19 pounds, but fluctuatin between 18-19. I did the propane test for the manifold gasket leak, no change in idle. I cleaned out the IAC valve, no change. I checked the torque of the throttle body bolts, all were good. I guess next I check the intake manifold bolt torque.
I did notice something wierd to me. It got dark out and I was looking at the plug wires to see if I was getting a spark leak someplace none foud. I did see a small purple spark continuously jumping from a bolt next to the water pump, right to the pully. I have never seen that before. Unless this is friction from the belt grounding?
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Friday, February 23rd, 2007 AT 5:32 AM
Tiny
JACK42
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That is the plug wire arcing to the engine. There is one misfire. It will NEVER run correctly until either A/C Delco or Autolite spark plugs are installed. Bosch Platinum have more driveability issues than any other plug I have ever seen.
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Friday, February 23rd, 2007 AT 8:07 AM
Tiny
CA441970
  • MEMBER
Did what you said, pulled the bosch plugs and installed the AC Delco Professional Platinums. The car runs 120% better. I can't thank you enough! Now I can start growing my hair back, I pulled most of it out trying to find vacuum leaks, bad sensors, coils, etc!
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Sunday, February 25th, 2007 AT 10:16 AM
Tiny
93SHELLOLDS
  • MEMBER
Okay so if you pull the plugs you have an put A/C Delco or Autolite spark plugs in it will run better? I'm sorry but that doesn't work. :( I have done that along with an a ray of other things.
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Sunday, March 8th, 2015 AT 2:10 PM

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