# Engine dies when I REV up the engine



## 04 Goatman (Sep 19, 2007)

Hey guys ever since I had mods done to my engine whenever I rev up the engine & let off the gas the engine dies as the rpm descends. This morning I drove the goat to work & on the way there i was turning around to go back home to get something & the engine died. I put the gear in park & started the car.Just as quickly it started up ,just as quickly it died . It did this for 3 to 4 times until i had to give gas immediately after the car started to keep the engine from dying. It was fine in the afternoon on my way home. It seems its worse in the cold morning weather. My car now idles @ 950 RPM in gear. Does anyone out there can tell me why my car engine dies whenever i rev up the engine & with the cam I have is the 950rpm idle normal in gear? I think the idle is too high . The guy who tuned the car I am guessing any lower than that the car will not stay idle. Here are the following mods done: comp cam duration @ .500 lift intake
222 exhaust 224, 112 degree lobe separation angle, lift intake .566 exhaust .568, comp cams 7.4 moly pushrods, new spring kit ( forgot what brand & spec), tune, stainless works off road header w/flow master muffler from cat. back, 2800 stall torque converter ( 262 RWHP).


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## 05GTO (Oct 6, 2004)

I would say your problem is in the tune, you are probably running too rich or lean. That or an O2 sensor problem, did you remove the cats and O2 sensors?


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## 6QTS11OZ (Mar 27, 2005)

Even with the 2800 stall, having 262 rwhp with your mods seems pretty low. I would point fingers at the tune as well. I would figure you'd be between 320 and 350 rwhp. That is low even on a Mustang dyno.


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## 04 Goatman (Sep 19, 2007)

Yes, the cat is removed but i don't know if the guy who did the tune removed the o2 sensor but i will find out this weekend. If there is a o2 sensor problem, wouldn't that trigger the check engine light ?


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## svede1212 (Nov 1, 2005)

your problem is more than likely the BAF (base air flow) of your idle. it is one of the many parameters that need to be adjusted, especially after a cam. in effect what's happening is that when you let off the gas the engine tries to use it's adaptive idle controls to keep it at desired RPM. that is done with timing and the idle air controller. timing is quick but the IAC is mechanical and slow. the engine depends on the BAF to have a starting point that's close to where it should be until the IAC can get in the picture. yours isn't where it should be. short answer. it's in the tune.


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## svede1212 (Nov 1, 2005)

oh yeah
PS, my cam is a 228/232 .611/.600 111 lsa and idles at 825 RPM smoothly


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