1994 rt bucking at about 2000 to 3000 rpm

whatthe

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1994 RT 31,000 miles bucking on deceleration between 2000 and 3000 RPM approx. and at steady throttle at those RPMs. This is something new. Car never did it before and have had it for about 1 1/2 yrs. I just changed the fuel filter thinking it was not getting enough fuel. Not the answer. I have read previous posts on the issue and people thought it might be a plugged cat and I do not have cats. At middle RPMS and WOT the car runs great. I have new plugs and new wires. If that were the problem wouldn't it be at all RPMs not just lower ones? My fuel pump was tested, it has 55lbs of pressure so that is working good. I have been told that the '94 does not have a tunable ECM so I can't do anything with that. This problem started about 2 wks ago and is driving me nuts. The previous posts have stated that this is normal but it did not do it before so I am thinking there is something wrong. Any input about experience with this and what I should look to do or try next would be greatly appreciated.
 

Camfab

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Welcome to the club, it's interesting to me that it just started on your car. I'm assuming its stock, is that correct?
 
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whatthe

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will recheck ignition cable and spark plugs I don't know if motor internals are stock when I bought the car was told work was done by Hennesy could be B.S. The changes that I can see are smooth tubes air filter and exhaust Plugs and wires are fairly new.
 

envy-me

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make sure the plug wires are firmly seated on the plugs.
 

Indy

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The Viper does have a tendency to buck a little at low speeds, but if you said it's a new issue, it can hopefully be fixed. Are you sure you TBs are synced properly? Driver side should open a tiny fraction before passenger side.
Maybe pull the plugs to inspect them (I know you said they're new, but you never know), and check continuity on the wires (maybe a faulty wire?).
 

jdeft1

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I bought the car was told work was done by Hennesy could be B.S.

Not enough info when purchasing a molested car...

Sounds like a tuning/fuel issue. What cam is in it? Does it pop and burble, maybe a backfire now and then through the exhaust when it 'bucks' on decell?? --- That may be normal with a no-cat car (even stock)....

-Cheers
 
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whatthe

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gentlemen thanks for all the ideas and encouragement to fix the problem I did re synch the throttle bodies and that did solve the problem I must have not pulled the right cable back fully enough the car is now running like an eight day Elgin watch
 

Camfab

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Glad to hear you solved your problem, I was thinking that your car may have been one of the first cars that's essentially stock that had a bucking issue.
 
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