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Idle Surge Issue After Head Gaskets

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Old 10-27-2009, 05:26 PM
  #1  
Lunatic50
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Default Idle Surge Issue After Head Gaskets

Okay, hoping to get this in the right topic - and hoping someone has the patience for my novel-like detail.

Just recently replaced my destroyed Fel-Pro 1011-2's for Cometic MLS + ARP Head Studs, and I now have Check Engine Light, Idle Surge, and Very Fuel Rich Condition.

Keep in mind the car ran perfectly fine on this setup before the Head Gasket went. It even idled fine on the blown head gasket!

*Car runs fine at first start up, but once it starts to warm up (get into closed loop) it starts to idle surge little by little until it finally dies. While the car is idle surging I have tried pulling the harnesses one by one on the IAC, CTS, and O2's. Vacuum reads -15 during cold idle (before tear down was closer to -17 or -18) but the air/fuel sits around 13.0:1 so I figured the rich condition is causing the low vacuum... (Or do I have a Vac-leak???)

*Cleaned MAF

*I have checked around for vacuum leaks, and to no avail so far. Checked the EGR for the plunger sticking open (but it is not hooked up or hanging open). Tried pulling the IAC and limiting air with two fingers and the car idled perfectly and the A/F was back to normal. During driving the car will move and under throttle car will sometimes pull hard and hold decent vac/(A/F) and other times will load up and fall on its face.

*Set TPS Voltage to 0.99.

*Have replaced Coolant Temp Sensor and O2's as they are the only codes showing in KOER self-tests.

*With KOEO Self-test car only shows one drivability effecting code which is 67, clutch/neutral safety switch. When depressing the clutch pedal with KOEO test running code 67 is eliminated. I don't know if this means 67 is irrelevant or not.

So if anyone has advice to offer then I would highly appreciate any help I can get! I am absolutely stumped!
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Old 10-27-2009, 06:41 PM
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mustangsneverdie
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make sure your intake is tightened completely thats what it sounds like to me
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Old 10-27-2009, 08:17 PM
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It's torqued down. Now rainy and dark; in the morning I'm going to check over all the grounds again. Maybe I had a dumbass-attack and forgot to hook up the O2 Ground wire.
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Old 10-28-2009, 11:00 AM
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O2 sensor ground wire was hiding from me. Reconnected it and it fixed idle surge/rich condition in closed loop, but still have CEL.
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Old 10-28-2009, 07:23 PM
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302army187
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reset the computer and see if it still shows.

I was going to say vacuum leak, or you cracked/warped block/head
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Old 10-28-2009, 07:38 PM
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mjr46
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the CEL is on cause you pulled connectors while running, you'll need to disconnect battery for a few min then reconnect and perform a base idle reset
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Old 10-28-2009, 09:59 PM
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Originally Posted by mjr46
the CEL is on cause you pulled connectors while running, you'll need to disconnect battery for a few min then reconnect and perform a base idle reset
Cool, thanks for the info - will have to do that tomorrow.
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Old 10-31-2009, 10:12 PM
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im having the same problems but no cel do you think my o2s are bad cts/iac/tps are new
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Old 10-31-2009, 10:26 PM
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mjr46
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Originally Posted by turbogt21
im having the same problems but no cel do you think my o2s are bad cts/iac/tps are new
what year mustang for one??? and doesn't matter.......run a koer test to see what codes may exist that you can't see
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Old 11-01-2009, 08:43 AM
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Originally Posted by mjr46
what year mustang for one??? and doesn't matter.......run a koer test to see what codes may exist that you can't see
its a 87 maf car
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