ROUGH IDLE, SLUGISH PERFORMANCE

[ZR1BANDIT]

started getting rough idle lately, worse with a/c on. not the map sensor, checked that. runs smoother at high rpm but still not right. also have nocking noise at idle but have been told that is the dual-mass fly wheel making the noise caused by the rough idle. anybody have any ideas???-------------thanks for any help-------------Greg

[WB9MCW]

DM FLYWHEELS DO GO OUT AS EARLY AS 80K MILES I HAVE HEARD!!!! PART OF THE REASON I PUT AN ALUM. ONE IN AND NOW GET TO LISTEN TO THE TRANNY GEAR RATTLE...BUT MY STOCK DM NOW SITS ON THE SHELF WITH 60 K ON IT ONLY!!!

[Z Factor]

started getting rough idle lately, worse with a/c on. not the map sensor, checked that. runs smoother at high rpm but still not right. also have nocking noise at idle but have been told that is the dual-mass fly wheel making the noise caused by the rough idle. anybody have any ideas???-------------thanks for any help-------------Greg

Hello Greg, and welcome to the forum. :handshak:

We need a few details like year, miles, what has been done in the way of mods, maintenance, etc., to better help you figure it out.

:cheers:

[Hib Halverson]

started getting rough idle lately, worse with a/c on. not the map sensor, checked that. runs smoother at high rpm but still not right. also have nocking noise at idle but have been told that is the dual-mass fly wheel making the noise caused by the rough idle. anybody have any ideas???-------------thanks for any help-------------Greg

Rough or unstable idle can be caused by a wide variety of problems. Poor performance can be caused by a wide variety of problems, too. Sometimes the causes of rough idle and poor performance are related. Sometimes they are not.

Check all ignition system components. Run the fuel pressure tests in the service manual looking for leakinjg or fouled injectors. Make sure the throttle body is clean. The throttle plates are clean and the throttle shaft bores are not so worn that the TB is leaking. Verify that the oxygen sensors are in good conditions. Make sure the engine controls' grounds at the back of the block are clean and tight.

Lastly, the factory Service Manual may offer additional information on solving a rough or unstable idle problem.

As for the dual mass, if it's making noise, particularly, if, when you turn the key off, you hear a "rattle-rattle" just as the engine comes to a stop, the assembly needs to be replaced.

Good luck.

[1990 quasar blue]

Since you will most likely have to remove the plenum, this site should help if you haven't done it before. http://www.bcvettes.org/?http://www.bcvettes.org/howto/


As for the dual mass, if it's making noise, particularly, if, when you turn the key off, you hear a "rattle-rattle" just as the engine comes to a stop, the assembly needs to be replaced.
Good luck.

Thanks Hib as this helps me too. I always thought the rattle when you shut it off was normal. I've been trying to chase down a vibration in the rear of the car and now I am wondering if that might have something to do with it.
:cheers:

[ZR1BANDIT]

CAR is 1990, and has 12,500 miles. heard also that a shorted fuel injector solenoid a cause for rough idle. has anyone ever heard of Haibeck Auto Technology in Addison ill. ??? they are suppose to be Zr1 pros---any comments ??? taking car to local dealer thursday for check-up, they said they have a zr-1 certified mechanic.---thanks ---Greg

[Aurora40]

As for the dual mass, if it's making noise, particularly, if, when you turn the key off, you hear a "rattle-rattle" just as the engine comes to a stop, the assembly needs to be replaced.

Good luck.
By "assembly", I assume you mean the entire dual-mass flywheel assembly has to be replaced? What could cause them to crap out with so few miles? My car does that, and has a non-nickel-balancing idle with under 22,000 miles. I was hoping a mere tune-up would cure the unsmooth idle... :(

[ZR1BANDIT]

new injector on number 2 cylinder, all better now thanks guys

[Z Factor]

new injector on number 2 cylinder, all better now thanks guys

Glad to hear it. =D>

When you get the chance, may I suggest you put your city, or at least your state in your profile. :thumbsup:

:cheers: