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Discussion Starter #1
so i just did a motor an trans swap. and now i have found out that if i tap the gas quickly the engine will die. also every once in awhile when brakeing the rpm's will drop to about 100 and then back up to normal and kinda bounce around when brakeing.

Now heres a little insite on the truck that is kinda related but dont know if its the problem.

I do know the brake booster is going out, would that be part of the problem?

The temp gauge needle barely touches the first "N" in normal, could the fact of it runnign so cold be the problem?

if info would be amazing.

Thanks
 

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what did you swap to? your info says 5.0l, but is that the old motor, or new motor? is it stock specs for 1988? is it computer controlled? carb? did you test drive motor in previous vehicle before putting it in yours?(i.e. did it have these problems before?) how about some more specific info on your setup so we can get closer to droppin one in the toilet rather than throwin turds at the house...
 

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Discussion Starter #3
new motor is out of a 91 stang still a 5.0. i used the upper and lower intakes from my 88 motor and put on the 91. efi. motor was already pulled so i wasnt able to test drive it but the engien sat for about 6 months before i purchased it
 

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mmmm sounds to me like a severe vacuum leak? Check all your tubing/hoses connections, maybe intake isnt sealed properly? As far as my knowledge of power boosters go, when they go bad you get a real bad hissing around the rod going into the cab to the pedal, loss of braking and a sudden urge to turn the convenient store into a drive thru(sorry tranny for the sudden throw into park)... didnt affect my idle any but that was a chevy... could always change the power booster first and see... does anyone know if the temp sensor is the same for the stang as the bronco? If they have different gauges they may have different sending units (i.e. voltages)...
 

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both of those engines have a different firing order.
 

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ahhh nice to know jopes.... wouldnt have thought that ford would have changed firing order on one 302 to another... hope you at least used the pcm from the mustang and not the bronco then? Hes absolutely right about the firing order:

http://www.302w.com/Firing-Order.aspx
 

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in order to use the ECM from the mustang he would also have to swap in all the sensors and harness and add a second O2 sensor in the left exhaust pipe
 

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wow... im so glad I got my engine out of a f150 instead of that mustang... although I have no O2 sensors from donor vehicle... brand new exhaust with no bungs, much less sensors... on the list, just not very high up there...
 

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Crusher Mike
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Heres the Deal I Swapped the motor in it, it is an 91 mustang block everything else is all bronco. We are using the HO mustang firing order (same as the 5.8) there isnt a problem with misfiring. After the truck warms up the Idle will fluctuate between 300 and 1200 rpms. I have cleaned the IAC, replaced the TPS(i had an extra), replaced the EGR, and pulled fuel pressure. We pulled the connector from the MAP sensor and the truck ran better so we replaced the MAP and the truck ran like crap again. I pulled codes and got I think 31 Something with the EGR. any suggestions? Thanks
 
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