1996 Oldsmobile Cutlass 1996 olds Cutlass rough idle

DEVO85

MEMBER
1996 OLDSMOBILE CUTLASS
6 CYL
FWD
AUTOMATIC
136,000 MILES

96 olds cutlass has rough idle
When driving hard, it does not miss a beat.
It doesn't appear to be starving for fuel.
When at curb idle if you raise the rpm to
4000 rpm the engine will cut out back and forth just
like you where turning the key off and on.
This happens exactly at 4000 rpm
Could it be TP Sensor?

4 Replies

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi:
Is the check engine light on?

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Thursday, February 19th, 2009 AT 1:43 PM

DEVO85

MEMBER
3 POSTS

Check engine light on-- only code was for O2 sensor
That sensor
has been replaced
Testing that I preformed is
1 Spark at coil packs
2 New plugs and wires
3 New air and fuel filters
4 EGR tests OK- clean with no carbon deposits
5 Bench tested TP sensor and mass air, both show they are working
6 Cleaned throttle body and idle control( idle control is working)
7 Checked all vac lines for cracks and soft spots
8 Fuel pressure tests showed pump pressure is within limits, filter not plugged, and regulator is working ok
9 Cyl compression readings where good with all cyl. Readings very close to each other
10 Engine vac is 19 in
11 Checked all fuses and electrical connections
12 Brake booster vac ok--- holds vac--line is ok
13 Lower and upper intake gaskets replaced 6 mos
ago---I still checked uppers and they are good
14 Checked the new plugs, just to make sure I didn't
crack one putting them in

Next step will be going to Lowes to buy rope