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Missing - Rough under WOT

Posted: Thu Mar 31, 2011 3:19 pm
by 1993SSEi
Pease help :sadeyz: . My Bonnie seems like it's not getting enough Spark. I changed the Ignition Wires, Plugs, Fuel Filter, Pump and it still hesitates under WOT or strong Boost. It runs fine when giving Gas slowly. It also doesn't hesitate if I down shift into 'D', but that's just the Gear advantage... So, I'm thinking Coils?

There are no Codes.

What would you guys do next? Replace the Coils?

Thanks :beerchug:

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 3:30 pm
by J Wikoff
Check the fuel pressure when the car is cold, and after it is good and warmed up. Make sure to check each with the vacuum line on and off the fuel pressure regulator.

I had a similar issue when my fuel pump was dying. The warmer it got, the less it could keep up.

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 3:50 pm
by 1993SSEi
Didn't think of that. I'll check it tonight and let U know. Thanks.

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 8:24 pm
by harofreak00
Plugged cat?

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 10:17 pm
by SUSPECT 0
I too would consider checking out the cat, if you were having an issue with your ignition system it wouldn't run good at all
( low or high rpm) is your new fuel pump the same as/equivalent to the factory one?

EDIT

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 10:22 pm
by 00Beast
I had a bad coil and the car ran fine at idle and >10% throttle, just started misfiring when I tried to accelerate. Don't get too far ahead of yourself. Checking the cat and the fuel pump are necessary and important, but lets not rule anything out.

Re: Missing - Rough under WOT

Posted: Thu Mar 31, 2011 10:31 pm
by SUSPECT 0
Beast, I was not trying to rule anything out, I said that it would not run good LOW to high rpm, I did not say that it would run bad at IDLE to high rpm. You said yourself that at 10% throttle (low rpm) you started to have problems.

EDIT

Re: Missing - Rough under WOT

Posted: Fri Apr 08, 2011 7:58 pm
by 1993SSEi
Update, BUT I STILL NEED HELP #-o (and thanks for all the suggestions).

The Fuel Pump has normal pressure and the Ignition Wires, Plugs, Fuel Filter, Pump was just replaced. I don't think the CAT is plugged, because if I downshift it runs fine at the higher RPM.

It only hesitiates under WOT, heavy Boost. It just feels like not getting Spark. If floored, it misses, at normal acceleration, it runs fine. After replacing all the above, the hesitation is the same and still there. So I'm thinking Coils.

Question, would you change the coils at this point? I see them on eBay pretty cheap, individually sold. Also, Are the three Coils the same (forgive my ignorance, have no clue)? Thx.

Re: Missing - Rough under WOT

Posted: Fri Apr 08, 2011 9:32 pm
by willwren
The coil testing procedure is in Techinfo. Use it before buying coils.

What octane of fuel are you running?

Re: Missing - Rough under WOT

Posted: Fri Apr 08, 2011 10:15 pm
by 1993SSEi
Always 93, never less.

Re: Missing - Rough under WOT

Posted: Thu Mar 15, 2012 10:30 pm
by laimisl
Good day,

I read this thread, and would like to know this answer that seems was not given to the below question of 1993SSEi: "Also, Are the three Coils the same (forgive my ignorance, have no clue)? Thx."

I may need to replace my coils too, and would like to know if I can mix and match from the tested good ones that I may find in JY.

Thanks.

Larry