I just baught my 92 Firebird with the 3.1 and it seems like the kid has really hammered on it. There are a few things I can't figure out and I was wondering if you guys might know the answers. First off, what octane grade of gas should I be using? Second, the car smells extremely like gas when started, there is no gas leak that I can see under the car, any ideas? Also, the spedometer dosnt work, I found out that it is an electronic gauge but I dont know where the sensor is so I can replace it, is it on the tranny? it has an automatic transmission and when I stomp on the gas to hard it will make a thud in the rear end, is that like a busted tranny mount or? and lastly, it wont Idle steady, it is fine when it is cold but oncei t warms up it starts to idle roughly. I just replaced the air filter and that didnt work. So if you guys know the answers to some of these problems, it would be greatly appreciated.

 

ok first off welcome to the boards,

do tomp's full tuneup.

for gas use regular 87

theres a speedo cable attached to the tranny its probably loose

and where exactly is the thud coming from? right under the shifter or farther back? if its right under the shifter its either a torque arm bushing or a tranny mount

hopw this helped

 

kretos I was told there isn't a cable for a 91,92 cause the speedo is electric.

 

oh true, my apologies

i'll check my haynes manual then and see wha ti can find

 

theVSS connector should be on the driver side, by the tail shaft of teh tranny. Smells like gas.........the pin hole in the fuel line like I had goiing along teh front frame.

 

1) 87 Octane
2) Check the fuel pressure regulator - let the car idle for a few moments, then shut it off, remove the intake plenum, and remove the vacuum line to the pressure regulator - sniff it - if it smells like gas, you'll need to rebuild your regulator.
3) Vehicle Speed Sensor - located on the driver's side, tailshaft of the transmission - you'll see the plug sticking out of the side of the tranny - it might just be unplugged (I'm an optimist)
4) Yep, tranny mount failure - don't even fart around with it, get the Energy Suspension poly mount - $27 @ Autozone. While you are at it, order the Energy Suspension Torque Arm Mount - $18, have to order it. You will thank yourself after the hassle of installing it!
5) That can be caused by the fuel, run some fuel injector cleaner through the car. Also, take apart the IAC (idle air controller) and clean it really good with some Throttle Body Cleaner.

6) TomP's TuneUp. Do it first. And replace that timing chain!

 

If the fuel lines check out OK, then the major tuneup should definately fix your gas-smell problem- click on it here: https://www.thirdgen.org/techbb2/sho...hreadid=162251 Don't skip anything, either. 99% of everyone skips "check timing", but that makes a big difference... so what if you've gotta buy a $40 timing light, a shop would charge you $40 to look at it ONCE.

Also, have you checked the exhaust manifolds where they meet the engine heads? Sometimes the bolt heads snap off and cause an exhaust leak at the manifolds. So the pipes may be OK but the leak is by the engine.

Along with what Doward said, here's the full how-to of cleaning the IAC system: https://www.thirdgen.org/techbb2/sho...hreadid=175177

 

ah excellent tom, this is exactly what i've been searching for

 

wow, thanks alot guys, I'll try all of these things. the thud honestly sounds like it is coming from around the rear right tire. I have been trying to replace the fuel filter for a while, it looks like it hasnt been changed since the car was made, its all rusted on so I am going to make my own rig, I got fittings that fit both ends of the filter, and I have some fuel safe tubing, think this is a good idea? could it be tied into the gassy smell? I mean the smell really is potent, I can smell it from inside the car some times, I really dont see anything leaking from underneath.

 

also, to add to all of this, Im not really a master mechanic lol, This is really the first car I am actually doing work on, I had a 79 Caddy that I planned on doing stuff too but I ended up selling it because I wanted a trans am. In the mean time I had to ride and couldnt find a T/A in my price range so I saw a kid selling this firebird for $1000 and I baught it. It needs to be painted because all the paint it cracked, the side birds are gone and the nose bird it partially ripped off, the left front fender is bashed in, the fron ground effects are ripped off, and the front bumper is crooked lol. I recently baught brand new Firehawk Indy 500s for it, and the alternator died last week so I baught a brand new one of those. The engine has like 136000 miles on it but like I said, the spedo stopped at that so who knows what it really has. When I crawled under it for the first time, I saw that the right exaust pipe coming out of the muffle is being held up by a bungy cord lol. It also needs new struts in the front. They have struts in the front rite? I tink its struts in the front, shocks in the back, correct me if I'm wrong. The other thing I am not sure on is when I break quickly, it pulls drastically to the left which is kinda scary, the e-break wont work (I cant even pull it up). the right signal light dosnt work so I have to push it up and down with my finger when I want to turn lol. What kind of stuff is worth doing to my car? I was thinking about an MSD ignition, I emailed them and they told me all the parts I would need. Thanks again for helping me out with all of this guys.