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Old Dec 30, 2008 | 09:14 PM
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Default Idle surge



Got a 98 Camaro Z has heads and Cam. Added a 90mm Fast intake and 90 mm FRE Throttle Body. Got it tune and car runs excellent and makes power. But after couple of months later developed a idle surge does it evertytime I start the car and it idle surges either if its cold or hot outside and even with the engine warmed up. Swapped out Throttle body with a PTM 90mm and idle surge still there. Tried and replaced IAC motor and TPS sensor too and nothing. HAVE a SES light on. Have a MAF code for low input. So I chnged out the MAF for another stock MAF. Problem still there. I need to try to disconnect battery and reset PCM. To see if thats going to help my problem. You guys got any thought or ideas? Any expierence this same problem before?

I have already looked for Vacuum Leaks didn't find any. But I don't know if my MAP sensor bad. Check it out yesterday was covered with a little bit of oil but I have a catch can on the car. I"M STUMPED! And Idle surge is driving me crazy!

PLEASE HELP!
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Old Dec 31, 2008 | 02:46 AM
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Go back to your tuner and have him check it out.
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Old Dec 31, 2008 | 08:06 AM
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Have your tuner check your TPS % with his laptop. I know mine reads 2% @ idle and causes surging @ idle. Pain in the *** that we have not been able to figure out. We will be changing over to a 01,02 PCM this spring. Hopefully this will cure the problem.
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Old Dec 31, 2008 | 01:49 PM
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Thanks guys. Any one else want to chime in on this. Please by all means post up. Thanks.
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Old Dec 31, 2008 | 02:04 PM
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I've had the same surge after multiple tunes. It started after the Fast 90 was installed.
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Old Dec 31, 2008 | 03:08 PM
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MAP being loose can cause this, make sure its tight.
Other than that, there are plenty of things tuning wise that need to be done right to get idle solid.

If it was working for months and now started to flutter, look at things that changed since then.
All I can think of are change in weather and possibly a loose MAP.
Parts like the MAF,TPS,IAC Etc... can just go bad I suppose but don't seem as likely to me.

If everything is solid mechanically no leaks or bad parts, then start looking into the tune.
Your tuner should know where to look to get idle in line.
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Old Jan 5, 2009 | 11:07 PM
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Originally Posted by DirtyJohn
MAP being loose can cause this, make sure its tight.
Other than that, there are plenty of things tuning wise that need to be done right to get idle solid.

If it was working for months and now started to flutter, look at things that changed since then.
All I can think of are change in weather and possibly a loose MAP.
Parts like the MAF,TPS,IAC Etc... can just go bad I suppose but don't seem as likely to me.

If everything is solid mechanically no leaks or bad parts, then start looking into the tune.
Your tuner should know where to look to get idle in line.
I already changed out the IAC, TPS and MAF sensors. Set TPS voltage at idle at .60 volts. Thats what its supposed to be at. Also disconnected battery car seem to have fixed the idle surge for a day only. Car idle normally and ran as it always has. Then the next day the idle surge came back. as I started the car and let it warm up.

I did notice the MAP sensor a bit loose the orange rubber seal that seals it up on the intake is all worn out on mine. The orange rubber seal is worn out and real thin. Could that be my problem? I tried replacing it but can't seem to find a replacement for it. Anyone know where to get one?
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Old Jan 6, 2009 | 09:52 PM
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Originally Posted by IVRedZ28LS1
Could that be my problem?
I can't say that IS your problem, I can say that WAS a problem for me.

Ran fine on throttle, but off throttle it would stumble like crazy.
Tightened up the MAP and all was well.


Here's what I did, seen others do something similar.
There's no perfect way to do this, just search around the Depot and Menards to find parts that will work for you.
May take some work but I think its worth it if you have the FAST off the car.
There are reports they fixed the large MAP hole on the newer versions of the intake but the old ones were notorious for loose MAP holes.


What your problem is I'm not sure, I think getting that MAP tightened down is a good place to start tho, also make sure that MAF is still working.

That's just where I would start, I can be wrong
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Old Jan 7, 2009 | 07:51 PM
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Thanks for the info guys. I appreciate it!
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Old Jan 7, 2009 | 08:24 PM
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x2 on the map sensor. the fast intakes have had past problems with loose fitting map sensors.
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Old Jan 7, 2009 | 08:57 PM
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mine does that too.. but no ses light no codes... i do have the fast 90mm and tb ...
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Old Jan 7, 2009 | 09:19 PM
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Same thing here,I have the fast 92 combo and this problem is driven me crazy too. Im going back this saturday to see what my tuner says. Dam fast intake are they really worth it...
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