hello everyone I used to be on here under the name onebadzee now I'm back. anyway I have a 1992 firebird 305/auto tbi and I was having an issue with the rpms bouncing so I changed the tps and that didn't fix it and a couple of days later I changed the iac and now the car wont start, it will crank and crank but wont fire up. it wont even start with the old one back in it. can someone please tell me what the problem may be??? thank you

 

nevermind haha tinkered with it and finally got it started it ran rough for a second but smoothed out now its running great fixed the bouncing rpms too

 

Must have sold the Z? What exactly did you do to get it running.

 

well it appears im still having problems, more then before. when i first put the new iac in and fired the car up it was like my injectors were spraying at full blast, so much that the car was smoking and couldnt burn all the fuel, do you think this may have fouled out my plugs?????? i pulled the iac off again and adjusted the pintle back alittle and put it back in and the car seemed to run ok but the idle is rough and too low and alittle all over the place, and the car is still surging in while driving around 1500-2000 the rpms are bouncing some, any tips???

 

1:15 after your first post you tinkered with the car and got it fixed.
Now you seem pissy because nobody jumped right on your question again from this morning? Lighten up!
There are adjustments you want to check for both your IAC and TPS, see if that helps: IAC and TPS Adjustment - ThirdGen.org

 

my bad was frustrated with car. can you explain the jumpering part in more detail? is it supposed to be unplugged or?

 

The TPS stays plugged in. What they're describing there is to use 3 wires to jumper the disconnected plug to the TPS so that it's still connected, but you can probe the wire connections with the test meter easier. I'd first try back-probing with your test meter while it's connected how it is now before messing with making jumper wires. The center wire is positive, one end wire is ground, and the other end is the signal wire to the ECM (not sure which is which). If your plug is marked A-B-C, then it should be A-ground, B-pos, C-signal.
Since your trouble started with the IAC though, you might want to check that first. Remove it and check the pintle length. From the mounting flange to the tip, it should be 1-1/8" or less. If it's longer than that, you need to adjust it. There are two different styles of IAC valves. One adjusts by pushing in the pintle while rocking it back and forth. The other, you turn it clockwise while pushing in. If you don't, or didn't adjust the IAC before installing, and the pintle length was too long, you could damage it.

 

now the original problem was the rpms surging around 2k. i replaced the aic and the tps and its still doing it, and i noticed today that it also does it in park if i rev it up to 2k rpms and hold it, the rpms will jump randomly. i checked my vacuum lines and grounds they seem good, any idea what i should try next???

 

Do you have a timing light? Check your timing, and see if the mark keeps jumping all over the place when the idle surges. Don't forget to disconnect the tan/black striped wire at the harness that's by the heater box first. Could be the distributor is badly worn/sloppy, or has a bad ignition module.

 

Ah yes the ignition module.