1997 Oldsmobile Cutlass Unsmooth engine at 2300 to 2500 RPM

Tiny
BROOKSORKOT
  • MEMBER
  • 1997 OLDSMOBILE CUTLASS
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 144,000 MILES
My car when going about 60 mph or between 2300 and 2500 rpm acts like it is spitting and sputtering along. It almost seems as though it does not want to downshift. Sometimes it starts right up like a fuel injected car is supposed to and sometimes it has to be cranked and even push slightly on the accelerator pedal. I have noticed when reving the engine up if you get it to roughly 4000 rpm it will cut out and drop 500 rpm and then go right back to 4000 rpm. It will cycle like this a long as you hold the accelerator at that place. Might be getting to much air or not enough. Almost like it has a govner like my lawn mower. I have not hooked it up to a computer and the check engine light is on. Only 144,000 miles, wonder why? LOL Wondering if any one has any idea what it could be. I have replaced the fuel filter and the fuel pump. Just looking for some ideas. Hopefully it will be a simple fix. Thanks for the help and sorry about the spelling. Kyle
Monday, April 27th, 2009 AT 8:27 PM

9 Replies

Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 110,189 POSTS
If the check engine light is on, start there. Most nationally recognized parts stores will scan it for free. Let me know what codes you find.

Joe
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Monday, April 27th, 2009 AT 9:06 PM
Tiny
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Joe, here is a list of the scan codes in the order they came out. First PO102 Mass Air Flow, PO122 Throttle Position Sensor, PO133 O2 Sensor, PO300 Random Cylinder Missfire, PO240 Catalytic Converter. I did get the codes cleared and the check engine light is off for the time being. I did buy some mass airflow spray and used it on the mass airflow box. The check engine light is still off but I have not drove it that much. What do you think, with all the read outs it spat out? Thanks
Kyle
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Thursday, April 30th, 2009 AT 3:02 AM
Tiny
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  • MECHANIC
  • 110,189 POSTS
Actually, one thing leads to another. If one of the items is bad, it could cause other problems that make the computer think different things are bad too. If you cleaned the maf and it hasn't come on, let it go. If it comes on again, check it ASAP before other things can be recognized as the problem.

Let me know how it goes for you.
Joe
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Thursday, April 30th, 2009 AT 2:24 PM
Tiny
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Joe,

I hooked up the scanner again because the check engine light came on. The code I got this time was PO420 Catalyst Efficiency Below Threshold. Is the catalytic converter partially blocked?
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Monday, May 4th, 2009 AT 9:37 AM
Tiny
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  • 110,189 POSTS
It could be.
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Monday, May 4th, 2009 AT 10:20 AM
Tiny
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Can I remove catalytic converter or will it give the computer an error?
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Monday, May 4th, 2009 AT 10:49 AM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
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It is against the law to remove it.
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Tuesday, May 5th, 2009 AT 11:10 AM
Tiny
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I am still having trouble. My car is still sputtering when held at an rpm of 2300 and 2500. If using the cruise control at a speed of 50 to 60 mph and you inquire a grade. The car will jerk somewhat violently for a while and then will down shift and run smooth. At which the check engine light will flash. The feeling is that the car can not decide to down shift or there is a pause or engine hesitation. The only code I keep getting is the cataliytic efficency is out of acceptable limits. Please help, Thanks
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Tuesday, June 2nd, 2009 AT 11:08 PM
Tiny
JUSTDON
  • MEMBER
  • 154 POSTS
I wonder if this could be a vaccum leak at the intake gasket or head!

I had the same symptoms with a Ford 3.0 and it turned out to be the lower intake gasket allowing small amounts of coolant into the crankcase. That's when I would get misfire and o2 sensor codes.

Just a thought.
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Tuesday, June 2nd, 2009 AT 11:57 PM

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