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PostPosted: Fri Nov 14, 2008 12:24 pm 
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First look at my freakout here: http://www.pontiacbonnevilleclub.com/forum/viewtopic.php?f=12&t=5332&start=220

Ok now that you read that...

I plan on changing out the coil bracket and checking plugs (maybe one got loose), but has anyone else ever experienced these symptoms? I doubt the trans is going because she feels just fine under normal driving conditions and even up to about 85% throttle...then it starts bucking, popping, surging, etc etc.

I'm ruling out bad gas because this only happens at WOT, and again, it feels fine when just driving around town and the country.

The best way I can describe this is that it feels like I'm hitting an RPM limiter. I watch my HPT when it happens and the O2 take STEEP dives down to ~600 while I'm still at full throttle. Timing doesn't drop, no KR induced, battery voltage stays steady...however, rpms and O2's graphs look like wicked mountain ranges. :???:

Thoughts?

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PostPosted: Fri Nov 14, 2008 12:26 pm 
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How old is your fuel filter?

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PostPosted: Fri Nov 14, 2008 12:37 pm 
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2 things come to ind (both happend to me at some point in ttime)

1) Simply a bad coil pack. RPM's go up and pack can't handle the thruput.

2) clogged exhaust. My cat was clogged and at higher rpm's the car was puttering all over the place.

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PostPosted: Fri Nov 14, 2008 12:49 pm 
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I changed the fuel filter in July.

That would suck if it was a bad coil, I just put these MSD's in.

How would I test for a clogged CAT?

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PostPosted: Fri Nov 14, 2008 1:02 pm 
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Cat - Go underneath and bang on it. If oyu hear stuff rattle (no the heat shield) it is probably bad.

Coil - Do you still have an old one you can use to swap test with? Or I think there is actually a procedure on here somewhere to test them.

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PostPosted: Fri Nov 14, 2008 1:08 pm 
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SSEi95 wrote:
Cat - Go underneath and bang on it. If oyu hear stuff rattle (no the heat shield) it is probably bad.

Coil - Do you still have an old one you can use to swap test with? Or I think there is actually a procedure on here somewhere to test them.


Yeah I know how to test them, just a lame process. :wink:

The CAT is a new Magnaflow I had installed last summer, so I'd be surprised if its bad.

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PostPosted: Fri Nov 14, 2008 1:41 pm 
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is the car throwing any injector miss fire codes??


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PostPosted: Fri Nov 14, 2008 1:51 pm 
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No codes. I can't seem to get misfires to scan...not sure which PID I'm looking for.

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PostPosted: Fri Nov 14, 2008 2:00 pm 
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does it do all this when you put it in reverse when you hit the gas or come to a stop, all the bucking and popping & missfire's?


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PostPosted: Fri Nov 14, 2008 2:10 pm 
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Full throttle only. I induce the symptoms by getting up to 100% throttle from either a stop or cruising at any speed and slamming the gas. I tried slowly easing the throttle up to 100% to see if it would still happen; it does.

So at idle, normal driving conditions, and <90% TPS the car behaves perfectly normal.

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Last edited by Allmachtige on Fri Nov 14, 2008 2:11 pm, edited 1 time in total.

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PostPosted: Fri Nov 14, 2008 2:37 pm 
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have you checked for radiator fluid on top of the block around the corners?? possibly a bad intake mainfold gasket might be spraying into the injectors,i had some symptons like that and it turned out the gasket was shot


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PostPosted: Fri Nov 14, 2008 2:46 pm 
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Would this only happen during WOT if that was the case?

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PostPosted: Fri Nov 14, 2008 2:58 pm 
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what is w.o.t? #-o


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PostPosted: Fri Nov 14, 2008 3:22 pm 
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sco99888 wrote:
what is w.o.t? #-o


Sorry, WOT = Wide Open Throttle (full throttle, 100% throttle, 100% TPS, etc).

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PostPosted: Fri Nov 14, 2008 3:36 pm 
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no i would red line it and it was fine, only when i came to a stop and reverse the needle would jump for the speedomotor from 0-70 and shoot back and 4th since i got it fixed i have no speedomotor & the odomotor has been on the same miles since i got it fixed, guy said cluster was bad but it has full power.


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PostPosted: Fri Nov 14, 2008 3:42 pm 
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sco99888 wrote:
no i would red line it and it was fine, only when i came to a stop and reverse the needle would jump for the speedomotor from 0-70 and shoot back and 4th since i got it fixed i have no speedomotor & the odomotor has been on the same miles since i got it fixed, guy said cluster was bad but it has full power.


I think my issue is different than yours. Mine is ONLY at full throttle.

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PostPosted: Fri Nov 14, 2008 3:55 pm 
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maybe a bad t.p.s sensor


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PostPosted: Fri Nov 14, 2008 4:00 pm 
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sco99888 wrote:
maybe a bad t.p.s sensor


Any ideas on what voltage I should see from mine?

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PostPosted: Fri Nov 14, 2008 4:19 pm 
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a broker or loose tps can cause intermittent burst of fuel from the injector and cause and unstable idle which will lead to poor performance,also the tps lever must meet the tps drive lever to function properly,i dont know the voltage but it might be between .1 and 1.0 volts


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PostPosted: Fri Nov 14, 2008 4:30 pm 
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Get a scan near WOT.
LTFT
STFT
MAF Frequency
TPS Voltage

You can check TPS with engine off. Around .4 volts with throttle closed & 4-5 volts at full throttle. Press the gas pedal slowly & check it 4-5 times. Voltage should rise evenly & not have any "gaps" were the voltage drops off.

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