I done a 4.9 swap with a 4 speed manual, when I start the car it idles ok,when I drive it idle stays high and when I come to stop light and push clutch in the idle stays high for a few seconds then idles down, it has only started doing this recently, didn't do this after I first did the swap.

...normal...one of the things that bugged me with the 4.9 and with a manual.

Do a search for "4.9 sail on" and ways to minimize it.

found the link: https://www.fiero.nl/forum/A...050119-2-049097.html

[This message has been edited by Mickey_Moose (edited 05-27-2014).]

Probably the ISC motor. Could try recalibration or just plain disconnect it. Have to blip the throttle on mine to keep it alive without ISC.

IF I REPLACE THE ICS WITH A USED ONE THAT I KNOW WORKS FINE DO I HAVE TO RECALIBRATE IT WILL IT WORK PROPER AFTER I INSTALL IT

If you turn the minimum idle down to 400 rpm and follow the idle learn procedure, it should improve.
Nothing worked for me until the idle adjustment.

turn idle down to 400? I have a manual tranny

Turning the idle down to 400 causes the PCM to command a quicker idle down, it will idle around 650 rpm. Its just a calibration trick.

i am going to do the idle learn tomorrow, but unplugged the ics just to see what would happen and when i did the car idled really high, everything a read on here about unplugging the ics says it makes it idle lower

Unplugging the ISC freezes the idle speed adjustment wherever it was when you unplugged it.

I am going to do the idle learn procedure this weekend,on the instructions posted by fieroseverywhere, the last step says to let the car idle in park and drive for two minutes each, what is the procedure for a manual tranny

quote Originally posted by ozzman333: I am going to do the idle learn procedure this weekend,on the instructions posted by fieroseverywhere, the last step says to let the car idle in park and drive for two minutes each, what is the procedure for a manual tranny

There is no "procedure" for a manual tranny as the 4.9 never came with one - just follow what is posted in that thread using the lower idle value of 400 - just ignore the step with it in drive (although if you have AC run that at full tilt for this step) - put the car in neutral for the park step.

Doing this is not perfect by any means, but it is the best solution and the problem will still exist. Just not as bad - only way around it is to hack the ECM programming and change the code (which no one has figured out).

I suppose you can always retract the idle screw and leave the motor unplugged and then adjust the screw to the desired idle - not sure if this would cause any other 'issues' or not. Never heard of anyone doing that.

I did the complete idle learn procedure on my 4.9 with a 5 speed manual adjusting both the IAC and the TPS per the procedure. My car ldles down just just like it should and idles at 750 rpm. The sail on adjustment is used to get rid of the high idle. Another issue with the 4.9 is the O2 sensor, the Bosch O2 sensor causes a high idle. I had to put a AC Delco O2 sensor to make my car run correctly.

Joe Sokol

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85 SE Daily driver with a 3.4 DOHC OBD II
88 Formula/GT 4.9 Allante Intake (My Baby)
www.fieroking.com

didn't get to my idle problem this weekend but hopefully this week. I had my chip redone and believe the idle was set to 800 rpm, when I do the idle relearn do I still set the minimal idle to 400 rpm