1997 Ford Thunderbird 4.6 rough idle when shifting into gear

[Jtavares88]

Ive owned my 97 TBird for about a month. Since ive bought the car its had a bit of a rough idle when i first shift into gear or I can sometimes feel it coming to a stop. I it may just need plugs and wires so I performed a whole tune up. Still vibrates after new plugs and wires and rest of tune up. After work today I'm going to check for vacumm leaks. Does anyone have any idea what the issue could be?

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[64ZCODE]

Hi there. It could be the EGR valve sticking partially open. The way to tell is to hook up a hand vacuum pump to the valve and put suction on it, at which point the engine should stumble and die. If it doesn't, then the valve isn't working properly.

Also, does the car have an intake air control valve (IAC)? It's a valve that opens and closes to control idle speed. If the IAC valve sticks, it can cause a rough idle. Locate the IAC and give it a few taps with a hammer and see if the idle stabilizes. Tapping on the IAC frees up the valve to close and is the way to diagnose the problem. If that is the problem, then the IAC should be removed and it may be possible to clean it or else it will need to be replaced.

Doug

 

[gtsm07]

If every thing else checks out and u still have the problem try this take the throttle body of the problem could be in the elbow between TB and intake manifold there will be a bunch of carbon oily crud built up on the floor of the elbow sum carb cleaner and a wire wheel end of a drill will break it up put some new gaskets see if that does it. If u try it let me know if it works. I had same thing going on in my 97 I got a 4.6 . Good Luck

 

[Jtavares88]

thanks guys its been awhile since Ive logged in here. I just delt with the vibration for a while and just recently gave another shot at correcting it. I had some rotted out vac lines behind the pass headlight going to the evap canister. Its really hidden and hard to get at. I went threw the inner fender.
I have power steering vibration at idle still when turning wheel. Im going to try flushing fluid out and putting in mercon v.

 

[64ZCODE]

Intake air control valve may be sticking. With engine running, try tapping it with hammer and see if idle improves.