HELP failsafe mode activated 05 mustang gt


New Member
Oct 21, 2019
Thank you in advance for suggestions. I have 05gt 4.6 SOHC, first I had codes p151a, p2004, and p2005 (codes associated with IMR). Here are some of the symptoms: idling is rough, shuts off by itself within 5-8minutes of idling and Engine Fail-Safe mode gets activated, the car seems to have issues passing 3500 rpm.

Mods: just bolt-ons nothing crazy, 4.10s, 62mm throttle body and tune(BAMA) with a little bit of suspension work

Background pertinent info - this car was involved in an accident causing minor body damage. After the repairs, there was speedometer malfunction when I dropped it off at a shop they had to bypass the speed sensor wire to fix it.

What I tried so far.
I have inspected if the carb was built upon the intake manifold runners (IMR), throttle body, MAF sensor, I also checked if power was coming to IMR motor which checked out fine so I switched the IMR motor first and did not fix it, SAME CODES WHERE STILL THERE and after changing IMR motor the car started to through p102 and p2106 codes + originals (p151a...) so I changed, MAF and TPS sensor, still didn't work. Then I started thinking can it be throttle body components causing electrical issues so I switched out throttle body with a brand new one still no luck the same issue and the symptoms were there. I don't know what else to check so I decided to install a charge motion plate (CMP) to solve the problem LOL!! So I installed CMP and tuned the car (from BAMA) hoping it will fix the problem but NO LUCK. All the codes that were associated with IMR are gone but p102 and p2106 are still there. I don't know what else I can do. Open for suggestions and thank you for your time.
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10 Year Member
Jun 13, 2007
Sounds like you still have a problem with the MAF sensor and the engine is going into failsafe mode. Make sure the wiring harness is properly connected and that the wires aren't frayed.