Ok guys....im new to this so im gonna give it a try.

I have an 89 Firebird and its bone stock. No Mods because i need to get it running right first. My problem is that the car jumps from 1000rpm to almost dying or does die. This occurs no matter how high you hold the throttle and only when its on "warm up". Now when it is warmed up it will idle between 500 and 1000. It keeps jumping around till i put it in gear then it only jumps from 500 to 600. So now here is what i got: its a TBI 350 auto tranny and again no mods except maybe having no CAT. I have replaced the EGR, EGR switch, MAP, IAC, Plugs, wires, cap rotor, ICM, O2. Now for my question....Could it possibly be the pickup coil or the External Coil. I just bought this car and I now know why i got it sooooo cheap. But I love Third gen F-bodies too much to just get rid of it. The only code i get is a 44 (O2 sensor lean). Im stumped...........

Thanks in advance :hail:

 

I also replaced the timing chain........i also forgot to say that the timing is right on.......all this parts replacement is due to the idle........i kept fighting with codes and finally all i have is 44.... my bad.... ok.... think that should be it

 

Have you checked your fuel pressure?

 

I guess that wasnt all I needed to say. I have performed all of the usual tests. Fuel Pressure, Vacuum leaks, Compression test, I have even tested most of the sensors on an ohm meter. Everything within specs. I also tested the lines from the ECM to the ICM and so on. This weekend I plan on changing the Coil over to a Blaster from MSD. I just dont think that will fix it. Its something simple and I feel it. I guess I am just tired of looking at it and have overlooked something. If the coil dont fix it, i guess its time to get a Distibutor or the pickup coil. Any other ideas guys.

 

If it's got a TBI 350, it's not exactly bone stock. Thirdgens didn't come with those.

 

3 thoughts here. How did you check the vacuum? An air leak would create a lean mixture fault code at the oxygen sensor. What vacuum reading did you get and at what rpm?

Coolant temperature sensor. Did you check the specs on this? An osciloscope would go down well here.

Did you check all the connectors to all the sensors you have checked?

Hope this helps.
Andy.

 

Sounds like a throttle body base gasket leak. Mine was doing the same thing. It had a big chunk missing but the crud made it hard to see.

 

I read into your post that the car runs ok, & this is an idle only problem. I doubt it's the pickup coil, I would think that would affect the car at all conditions, especially hot. Have you checked the throttle position sensor. See the tech articles on how to check & adjust the throttle position sensor & how to clean your idle air control.

 

i'm having the same problem with mine (1990 3.1 mpfi)
once i get to a certin rpm it dies out, or if i let it idle for too long, also smoke comes out from somewhere around/under the rotor after awhile.
seams to run lean.
i replaced the spark plugs, rotor and cap,cables, & fuel injectors.
did a fuel pressure check, came out ok, no error codes, throttle body senser is ok, batery and alt is ok.
i'm wondering if it might be my gas...

 

FU-Q
Maybe you should post a new message for your car. What type of fuel injectors did you use? New? Rebuilds? Used? I'd check the injector coil resistance regardless. Should be 11.8 - 12.6 ohms. Where is smoke coming from? Rotor, meaning distributor rotor? If you are convienced the fuel system is ok, maybe next place to look is to pull the distributor for rebuild, meaning ignition module, pick up coil, & maybe the reluctor/ shaft assembly. If you do pull the distributor, for sure replace the o-ring on the the distributor body or you will have a terrible oil leak.

 

pull the distributor cap, try to laterally move the rotor/shaft if it moves back and forth then you either need to replace the distributor or rebuild it, including bushing...will and can cause bad idle, dying out ect. its worth checking into since if it is good then all you are out is some time.

 

i replaced all the injectors with new ones...

 

maybe its got a lot of carbon buildup in the passageways,buy the cleaner thats safe for o2 equipped cars and clean it out(t.b.i)..i had a similar problem on my older t./a it had the tpi engine and it was the throttle position sensor. i re adjusted it..cleaned out all the i.a.c pasages..took eveything apart and cleaned it somehow problem went away..i hate that surging..the tach up and down ..

 

mechanicalmehem and FJK THANK YOU!!!!!

:hail:

I checked the TPS and this time when i hooked it up to the OHM meter i got a .32 . I adjusted it to be around .51 or so and it did seem to run a bit better.....then i came back here to see any last minute posts. I pulled the distributor cap and low and behold it did wiggle....not side to side but front to back....I went down to the local Speed Shop and got me an MSD replacement

Well guys she runs great....its like a new car again. At first I didnt even know you could adjust the TPS and I also didnt even think of a simple thing of trying to move the whole distributor. One last question though.....Should I have changed the whole upper parts(Cam, lifters, rods, rockers)? I do have a bit of a tick from the drivers side. BUT IMMA HAPPY RIGHT NOW....i get to cruise my car on labor day.....thanks again guys.....