I have had several posts on here about my Fiero. I am still having a hard time getting this thing straight. When I think I have it right it resorts back to what it was doing. The dam thing will cut off at stoplights when its up to temp. It seems like when I get the car up to temp the rpms drop(600-1000). If I pull in my driveway I will put the car into reverse and it cuts off. It starts right back up and then I put it in drive and the same thing. I cant figure it out? Sometimes it seems as if it has a miss when in gear and sitting still(the engine idles erratic0 i have replaced the following: plugs, pcv,crancase filter, air filter, tps,iac,belts,o2 sensor, vacuum lines, fuel pump, fuel filter. It is a 86 2.5 duke. I am pretty sure the timing is good but when I tried to rotate the distributor it wouldn't budge(yea I loosend the retaining bolt). I cant figure out why it will run good for a brief time and then I cant get it right. Please Help!!!!!!!

Your TCC solenoid is most likely bad. I would unplug it and see if your problem go's away.

For more information and other diagnostic tests, read here.

[This message has been edited by AutoTech (edited 04-14-2008).]

How do you know for sure the timing is good if you are unable to rotate the distributor for adjustment?

Its not the TCC. I unplugged it and it still cuts off. As far as the timing I am not sure its right. It runs like a top sitting still and even runs good all throughout the gears. It just that after driving it for a few miles when I stop and try to back-up in my driveway the thing idles down to 500 rpms and cuts off. What else could I check? I adjusted the TV cable. I pushed the silver tab in and pulled the cable out tell it was seated and then pushed the butterfly WOT. Is this the right way to set it?

A few years ago I owned an '88 4 cyl coupe (automatic). I had serious idle issues, it threatened to die at every stop light. It seemed to run ok when cold, but idle quality was lousy when it was warmed up. Forget about using the A/C, if it was on it would die at every stop light. BTW, the motor was new old stock from Pontiac with only about 2xxx miles on it.

I tried a lot of fixes, replaced plugs, wires, module, coils, TPS, IAC, etc.... Nothing really helped. Then, almost as a last ditch idea, I replaced the ENTIRE throttle body injector unit - Fiero Dave in Wisconsin had a couple of NOS Pontiac units, and I ordered one and installed it. BINGO!

I'm not sure if it was the new fuel injector, or the new gaskets & seals, or maybe the Fiero gods had decided that I had sacrificed enough money to appease them, but it worked. Idle quality was fantastic hot or cold, and I could use the A/C again!

I'm not saying that this will fix your car, but it might be worth a shot. J.C. Whitney carries rebuilt throttle body units for the duke.

GOOD LUCK!!

Thats worth looking into. I did mess with the timing and the spark knock is gone and it has more power. It doesn't stall when trying to back-up. The idle is still a little low for me(500-700). Hey Doc John do you have a JC Whitney part #? How much was it? Its the 2.5 duke w/auto

J.C. Whitney catalog is sitting right in front of me. Part number is MM760731F, and it goes for $259.99 + S&H. You'll need to specify year, make, model, engine size, and possibly the OEM # on the throttle body. Before I ordered then one from Fiero Dave, I ordered one from J.C. Whitney, but they don't carry one for the 88 duke - but your 86 should be no problem.

Fiero Dave? Is that the fiero store? I found the one at Jc Whitney. Where should I get one from? I was reading somewhere that the throttle cable could cause this. I do know that my throttle pedal is a little stiff, it doesn't appear to be binding. How hard are they to replace?

http://www.fierodave.com/

He used to have some good close out deals on OEM stuff, but he seems to have less and less as time goes on and OEM parts supplies dry up.

The throttle body was pretty easy to replace. I've never had to replace a throttle cable, so I can't say much there.

BTW, where in VA are you located?

I'm in Gloucester..........Newport News area

I didn't see a CTS (coolant temp sensor) in your list of replacements. Worth a shot since they are less than 10 bucks.

CTS, what will that do? I know when the temp gets to 220 the electric fan comes on.

Coolant temp sensor tells the ECM what the engine temperature is. If the ECM is being "fooled" by a bad CTS, it will make the ECM think the engine is cold when it really is hot, or vice versa. ECM also controls the injector pulse width, so the mixture could be richer (or leaner) than it needs to be since it is being tricked by the faulty CTS.

Got Ya.............I see the light. Thanks

You could also rebuild the throttle body. Autozone sells a TBI rebuild kit for $33. (part num 96-617) I used the similar kit for the '87 Duke and it cured a bad idle I had. It's just gaskets and o-rings but it did the trick for me.

Hudini,
Thanks for the input, I found a local Autozone that had the part in stock. That seemed to do the trick. This has been a long road and I hope I am at the end.

Glad to hear that. The weird thing is when I did the TBI rebuild I never noticed anything wrong. Nothing broken or cracked and nothing out of place. But it worked and the car still runs fine.

Maybe the Fiero gods just wanted to test how dedicated you were. lol