1987 Gt, Weird Problem. - MustangForums.com

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1987 Gt, Weird Problem.

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Old 05-11-2008, 08:41 PM
  #1  
Riceinator
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Default 1987 Gt, Weird Problem.

hi guys. My car is still sd, so i think this is the most appropriate place to post my question.

When I first start the car up, it idles nice and seems to drive with full power. But after driving for a bit and getting up to operating temperature, everything gets all weird. When idling, it idles rough and kind of feels like a miss. Also, when giving it anymore than light gas, it seems to surge (kinda feels likebucking)at anything more than 2k rpm. When I watch the tach, you can see the rpms bouncing around. It only does this when it is warm. Sometimes it does it worse than others. This problem has me frustrated and confused. Any input is welcome.

oh yea, and so far, i have replaced plugs, wires, fuel filter and tfi blaster coil. And yes, i gapped the plugs correctly.

Thanks in advance.

edit: it also feels like it lacks power once it is warmed up.
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Old 05-12-2008, 05:11 PM
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stangbanger87
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Default RE: 1987 Gt, Weird Problem.

possibly in the o2 sensors or in the egr from what it sounds like to me .
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Old 05-12-2008, 09:40 PM
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Riceinator
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Default RE: 1987 Gt, Weird Problem.

ok, how would i go about testing the o2's and the egr?
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Old 05-14-2008, 04:00 PM
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Vertastang
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Default RE: 1987 Gt, Weird Problem.

mine did that somtimes to does it run fine on like Cool days and act up on hotter days??? mine did almost the same issue your saying and it was the temp control sensor changed that and the issue went away.
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Old 05-17-2008, 09:27 PM
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jayh88gt
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Default RE: 1987 Gt, Weird Problem.

check for vacuum leaks. make sure vacuum line to map sensor isnt dryrotted

otherwise, how are the wires, cap, and rotor?

sounds like its loaded up and the plugs are fouled but u gotta figure out why

what happens if you repeatedly beat the snot out of it does it clear up?
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Old 05-17-2008, 10:43 PM
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67mustang302
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Default RE: 1987 Gt, Weird Problem.

Check the ECT, EGT, EGR, pull codes etc.
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Old 05-18-2008, 10:57 PM
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jayh88gt
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Default RE: 1987 Gt, Weird Problem.

oops i see new wires now

id bet vacuum, but double check timing and fuel pressure
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Old 05-20-2008, 09:15 PM
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Default RE: 1987 Gt, Weird Problem.

thanks for the input guys, but I believe I have it tracked down to the ignition module getting hot and acting weird. The part comes in tomorow, should be on by tomorow night. If it doesnt fix it, I will come back and ask again. Thanks again guys.
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Old 05-25-2008, 02:58 AM
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Default RE: 1987 Gt, Weird Problem.

did that fix it? ignition module? I am having a very similar problem with mine. i put new plugs in after getting it back together and once i start it up it runs good.. but then after it runs for a little bit it runs like crap, bucks, and the plugs have a bunch of soot on them. i checked the fuel pressure, did cap, rotor, wires... whats left? 02 sensor, egr(it has egr deleted and has for a long time), ignition components, fuel injectors?
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Old 06-15-2008, 05:44 PM
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Default RE: 1987 Gt, Weird Problem.

the ignition module did not fix it. I am still stumped here. I havent had the chance to pull codes yet though.
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