1995 L27 Silhouette - Surging idle at warm start-up
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1995 L27 Silhouette - Surging idle at warm start-up
It'* done this since I bought it and I've had trouble figuring out why.
When I start it while the engine is warm (100* or so), the idle will fluctuate by about 1000 rpms but will not stall. If I give it a little gas it will smooth out.
I've reset the computer
Cleaned the TB
Cleaned the MAF
Cleaned the EGR passage
It has a new fuel pump, intake, EGR, coils, ICM, o2 sensor, plugs, wires, PCV valve, air filter and fuel filter.
No codes, stored or otherwise.
It runs pretty good otherwise. Other then what sounds like an exhaust leak (I'm thinking cracked rear exhaust manifold on that) and possibly a bad harmonic balancer (which I planned to replace next month).
Any ideas?
When I start it while the engine is warm (100* or so), the idle will fluctuate by about 1000 rpms but will not stall. If I give it a little gas it will smooth out.
I've reset the computer
Cleaned the TB
Cleaned the MAF
Cleaned the EGR passage
It has a new fuel pump, intake, EGR, coils, ICM, o2 sensor, plugs, wires, PCV valve, air filter and fuel filter.
No codes, stored or otherwise.
It runs pretty good otherwise. Other then what sounds like an exhaust leak (I'm thinking cracked rear exhaust manifold on that) and possibly a bad harmonic balancer (which I planned to replace next month).
Any ideas?
#4
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I'm having the same problem with my 4.0. I have to ask, have you had any issues with difficulties starting the car? Or does it fire up after 2 or 3 cranks, then surge?
MAF cleaned, IAC cleaned, TB cleaned, air filter fine, fuel pressures fine
**subscribes to thread** because I'm at wits end.
MAF cleaned, IAC cleaned, TB cleaned, air filter fine, fuel pressures fine
**subscribes to thread** because I'm at wits end.
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Originally Posted by Archon
When you cleaned the throttle body, did you clean up the idle air control valve and passage really well?
Originally Posted by Archon
Check for vacuum leaks, also.
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Originally Posted by Jim W
I'm having the same problem with my 4.0. I have to ask, have you had any issues with difficulties starting the car? Or does it fire up after 2 or 3 cranks, then surge?
MAF cleaned, IAC cleaned, TB cleaned, air filter fine, fuel pressures fine
**subscribes to thread** because I'm at wits end.
MAF cleaned, IAC cleaned, TB cleaned, air filter fine, fuel pressures fine
**subscribes to thread** because I'm at wits end.
Does yours start hard? My 3.4 DOHC Cutlass does and I know the injectors aren't leaking because it still does it even if I hold the pedal to the floor. I'm suspecting wiring problems there.
I just went through the cold surging with the DOHC. It had a chunk missing from the plenum gasket!
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Originally Posted by BillBoost37
A can of carb or TB cleaner is your friend at finding vac leaks. This sounds very much like vac leaks.