Engine idle and gas problems
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Elder User
Joined: Sep 2003
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From: Myrtle Point, Or
Engine idle and gas problems
Ok, I have a '89 Bronco with a 351 with 6,000 miles on it, that i rebuilt myself, but there are a few bugs I can't get worked out.
When giving it gas for a short spurt, like at a stop sign when there are peaple in front of u, when i let off, the motor will try to fall flat on it's face, and even sometimes die. I've replaced the TPS, O2 sensor, and PCV. Wires are new and also a new cap and rotor. new plugs. It only does it when the motor is warm. Any ideas?
Also, my gas milage sucks. when the motor was first rebuilt, I was getting my norm 10mpg, but for some reason, it dropped to 7 in a week, and I can't fiqure out why, oh, and the tranny is now rebuilt with only 600 miles. I didn't change anything when the milage dropped, but i can't get it back up to norm for the life of me.
Important info
I just found a small crack that I've been hunting for a while in my upper intake manifold. Is it possible that this crack is what brought my milage down? Also, It only leaks when it's warm and I run it hard, I then here a vaccuum leak after that.
When giving it gas for a short spurt, like at a stop sign when there are peaple in front of u, when i let off, the motor will try to fall flat on it's face, and even sometimes die. I've replaced the TPS, O2 sensor, and PCV. Wires are new and also a new cap and rotor. new plugs. It only does it when the motor is warm. Any ideas?
Also, my gas milage sucks. when the motor was first rebuilt, I was getting my norm 10mpg, but for some reason, it dropped to 7 in a week, and I can't fiqure out why, oh, and the tranny is now rebuilt with only 600 miles. I didn't change anything when the milage dropped, but i can't get it back up to norm for the life of me.
Important info
I just found a small crack that I've been hunting for a while in my upper intake manifold. Is it possible that this crack is what brought my milage down? Also, It only leaks when it's warm and I run it hard, I then here a vaccuum leak after that.
Thread Starter
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Elder User
Joined: Sep 2003
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From: Myrtle Point, Or
Originally Posted by CLHAY
That crack is your vacuum leak thats likely screwing up your idle.
Elder User
Joined: Mar 2003
Posts: 522
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From: Warren, MI
Originally Posted by mustangman65_79
It's not big enough to cause it to die though, and it only opens up when the motor is warm and i run it really hard, sometimes not even then. The gas prob I think might fix with a new intake, but the motor stumbling and dieing is really ****ing me off
Adam
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Elder User
Joined: Sep 2003
Posts: 533
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From: Myrtle Point, Or
The crack is on the front os the upper, it curves up from the bolt to the runner, then back to the bolt, looks like it happend from stress of both being and old intake and brittle, I know I didn't over tighten it.
Freshman User
Joined: Nov 2003
Posts: 34
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From: Westchester County, NY
Again, my sense (although limited) is that the "slight " crack is creating enough leakage to unsettle your idle!
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