91 thunder chicken. car shaking.

i have a 91 thunderchicken.
. first off. my gas gauge, temperture gauge and speedometer dont work. could i possibly replace it with another one and be ok?

second, the car will idle good in park and nuetral, but when you put it in other gear, the whole car shakes until you hit the gas and most times it stops shaking, sometimes, it shakes while at idle in gear. a mechanic told me to have a shop check my sensors. could be a bad sensors. i checked the motor mounts and the guy told me it wasnt rocking when i hit the gas in gear. and he ruled out the transmission too. they also said it could be a vaccum leak, if that was the case how would i find out where its at?
changed plugs also

third, my turn signals dont work but all othe relctrical stuff work. could replacing the ignitions switch work? on my 89 the blower motor, turn signals and brighst didnt work until i replaced that switch.

i got a open plug by the sensor on the air breather hose. cant find a connection to fit it.

and lastly, would almost everything from a 89 thunderbird fit a 91 thunderbird, there both 3.8

thanks

1. You need a wiring diagram to troubleshoot the faulty guages. I have bought some OEM elctrical manuals off of Ebay. Here is a link to some for your year and they are worth the money! Buy the EVTM for your electrical problems and buy the shop manual to keep your "Bird in shape. These OEM manuals are much better then any other manuals you can buy. http://shop.ebay.com/items/?_nkw=1991+thunderbird+manual&_armrs=1&_from=R40&_mdo=
2. If it is a vaccuum leak you can spray WD-40 on the vaccuum hoses (move the can slowly) and see if the engine shaking stops. The manual that I told you about above (the EVTM) has a vaccuum diagram so you can see where all of the hoses are that you have to check.
3. Your turn signal problem could be due to a faulty multifunction switch (directional switch) which you may have mistaken as the ignition switch.
4. The EVTM manual will show where all of the connectors go. See- I told you the manual was worth it!
5. Can't help you with this one. Ask at a junkyard and they can tell you what is interchangable.

I had the identical shaking problem you described a few months ago. For a while no one could figure out what it was but Sears actually ended up fixing it. For me, it was a bad DPFE sensor (http://rockledge.home.comcast.net/~rockledge/RangerPictureGallery/DPFE_Images.html) which I had never heard of until then.
I also had a check engine light acompany the shaking, which very recently came back, so I'm off to Sears again in a few days. But the work they did previously did stop my shaking.

I have no assistance for the shake, however, an 89 and a 91 with the same motor and trans are 100% interchangeable to my understanding.
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