I put injectors in my 350 with bosch 3s and ever since the idle was low it was missing and stumbling. Ive looked for vacuum leaks but haven't found any. I bought a new IAC and re adjusted it and it would run great for a few seconds nice and smooth and then go back to crapping out. Now the tps is out of adjustment along with the idle air along with the IAC because I don't know what im doing and I cant leave things alone... I started out again with setting the timing at 6 degrees BTDC. now I need to know what to do. I am trying to take the car out of town this coming weekend and leaving Friday morning for a car show and need it by then and I need your guys help with this. thanks!

 

schroeder.......follow this procedure TO A TEE! It will get ya going.

https://www.thirdgen.org/newdesign/tech/tpimod2.shtml

 

Just for added thought, I found I had to do the procedure a couple of times. Changing one setting affected the other ( or maybe I just wasn't good enough!). I also thought I had no vacuum leaks, but found some bad ones where the runners meet the plenum and intake. Re-installed with a little RTV on the gaskets, and no issues.

 

It took 3 times for me also.

 

Ive tried following that to a tee but it just seems like im going in circles. I get the idle air right and it runs somewhat better then move over to the tps and set it at .54 volts and it just goes back to stumbling and missing and choking itself out. I cant for the life of me get the iac and tps and idle air where it should be! Which one do I start with? Cause im just chasing my tail in circles

 

OK. This post is by Vader on here. It is the most comprehensive procedure on setting this stuff. He is a Moderator on here and knows his stuff. I used this procedure, in this order, and followed it with good results. I couldn't locate it yesterday. You may need to take your IAC out and clean it. They're steps showing that also. Scroll down to post #4 and start from there.
https://www.thirdgen.org/forums/tpi/...Position+VADER

 

The iac is brand new, but ill give it a try when I get home. Thanks man!! Times ticking before friday morning... haha

 

Okay so I followed that procedure to a tee and I had the est unplugged, iac unplugged and fully extended, timing set to 6 degrees btdc, I cant tell where it was idling at cause my tach is about 3000 rpm off but it ran and idled perfect! Just where it sounded arounr 400-500 rpm, shut the car off, set the tps at .54, plugged everything back in, reset the ecm, and there it goes again, barely idling and has a miss to it. Tps is good iac is new new plugs wires cap and rotor new intake gaskets no vacuum leaks I don't get it...do I need to set the idle higher before I plug everything in again? Going down the road wide open it runs amazing. Once it gets thru choking it self out it lays mean burnouts, it just wont idle and misses and runs super rich. Im at a loss...and im leaving with it friday morning running like crap or not haha. Any ideas??

 

Cleaning the throttle body itself is a good idea when cleaning/replacing the IAC. Those butterfly valves get caked up with crud. You'll never see it until it's off the car.

Timing at 6° is good.

I set the idle screw with the EST plugged in.

My method of setting this is to forget about trying to get it at 400 RPM with the IAC valve closed and instead get the car up to full operating temp. Around 200°F. Then with WinALDL and a laptop, set the car so that at idle, the IAC counts are in the 30 range (transmission in PARK and turning the adjusting screw on the back of the throttle body.)

30-50 IAC counts is good. Closer to 30 is better.

At that point shut it off and adjust the TPS last. I'm assuming your TPS is working correctly. It doesn't have to be at exactly .540 volts. Mine is at .575 right now. If it works at .540 to around .630, you're fine.

Also remember that when you unplug the battery for 5 minutes to clear the code that sets when you had the EST wire disconnected while setting the timing, that when you first re-connect the battery, the ECM is going to run on baseline parameters for a good 20 minutes of continuous driving. It needs to re-learn your driving style all over again. Simply driving around the block won't do it. You need to drive the car. Expect it to hickup a bit and not feel like it's as smooth as it should be when you first re-connect the battery cables.

Since you did cap/rotor, plugs, wires, I'd throw in a new ignition coil as well. If it's weak you'll never get a good spark.

 

I dont have a laptop and a winaldl deal. Something has to be simple. It will don
Run perfect with est unplugged and iac all the way out and sounds perfect. Idles great. Then you plug it all in and it runs like crap again. But only idling. Won't idle. Sounds like it has a loopy cam and misses. But down the road it runs amazing. It's ran better than it ever has. Something has to give...