First off my car is an 86 firebird, 2.8L. A while back my car started losing power and would have alot of trouble reving past ~3500 RPM. It would also stall sometimes when I came to a stop.

Since then I changed the pickup coil, ignition module, fuel filter. It started running better but as soon the car would warm up it would idle absolutely horribly. The idle is as low as 500 RPM and is struggling to stay running without me giving it gas. Another thing is that if I suddenly press the gas there is a very noticeable drop in RPM and most of the time causes the car to die. If it doesn't die then it seems idle better for maybe 15-20 seconds before its back down to about 500 RPM. Also while playing around with playing around with timing i got code 44 twice.

A friend took a look at my car and suggested that the CTS or possibly the fuel pressure regulator need to be changed. I've changed the CTS but still got the same problem. I don't think its not an ignition since pretty much everything has less then 7000 km on it (Spark plugs/wires, module, pickup coil and ignition coil) and Im gettin nice sparks. I'm going to borrow a fuel pressure gauge next week to make sure that fuel is not a problem.

Wondering if anyone has any idea whats wrong. IAC? FPR? MAF? TPS?

 

Hows the Cat converter?

 

Found out it was hollowed out

 

A vacuum leak seems like the most likely cause, with the engine stone cold, spray some starter fluid around vac lines while its running, see if it does anything to the idle speed, just be careful not to hit anything hot, ie. exhaust manifolds, the stuff is flammable afterall, and do it with engine cold of course.
CTS wouldn't cause those problems, the sensors you listed could though, find out what code 44 is, I don't recall offhand, but thinking its MAF code maybe? Check if you're leaking gas anywhere. Could also be injectors or fuel pump maybe, and check all your fuses.

 

I was trying to find some vacuum leaks with propane but couldn't really find any. I also changed some of those plastic vacuum hoses just to be on the safe side. Also when my friend came to look at it he said a vacuum leak bad enough to cause these problems you would be able to hear it. There might be a small vacuum leak but i don't think its the only problem.

I've also ohmed all my injectors and all were about 16.8 give or take 0.2. I hear the fuel pump when I turn the key on but I still want to check the fuel pressure.

Code 44 is lean and its only showed up twice when playing with timing.

Ill double check my fuses but i think they are good.

Another thing i was wondering though is that when i turn the car off i hear what i think is the IAC running for couple seconds. Is it supposed to do that? Haven't payed much attention to that in the past but its something that i noticed recently

 

Try the idle relearn process, I would link it if I still had it bookmarked, you will have to search, if it is the IAC it will be an electrical gizmo type of noise, and its the only thing in the engine compartment that can make that kind of noise,lol, kind of sounds like an electrical motor, or fuel pump or something.

 

Its exactly that kind of noise, but is it supposed to do that when the car is turned off?

I remember seeing something about an idle relearn ill try to find it

 

I honestly don't recall, sadly I have only run my car a few times, found out the block was cracked and just now got it running again with a new engine, but still haven't run it longer than a few seconds at a time, waiting to get my accessory drive belt system worked out before I do. I do seem to remember the 2.8 doing a lot of that though, don't think its done it on this engine though(same IAC) but also when it was on the 2.8, I tried an idle relearn, once i got it to not stall out, it kept jumping idle speed, had a weird high pitched whine, but both eventually stopped, so i think it was relearning idle, cause it leveled off after that and idled normal without that weird noise.

 

86's don't have an idle relearn...

Yes, the IAC makes noise when the engine is turned off due to setting itself at "Home" position for next engine start.

Don't just check the vacuum lines, also check the rubber ends on the PCV and idle air pipe connections for cracking and tightness. Check the intake bellows for the same. Then remove the MAF and look in the back, engine side. If the orange square of film isn't flat when held up to light, the MAF is bad. I've had MAF sensors go bad without throwing a code 33 or 34, but a code 44/45 instead.

Also check to make sure the EGR valve and solenoid aren't stuck open.

 

Checked for vacuum leaks again and still couldn't find any. Checked the MAF too and the orange film does look like it's abit warped but when i hold it in direct light it doesn't look that bad. I also remembered reading here somewhere that if the MAF is the problem then the car should run better with it unplugged, is that true? I tried that and my car simply dies within seconds.

Another thing I noticed is that it does not like any load. If its in park and idling decently and I start to turn the wheel the RPMs drop and it sounds like it's about to stall. Same thing happens if I put it in D

 

That's because they both put load on the engine, the first due to the power steering pump, the latter because you're adding the rotational weight of the transmission. If these things haven' done as recently as they should have been, do them: fuel filter, air filter, pcv valve, oil change, pull the MAF or intake hose off the throttle body, if there is a bunch of black crap built up around the throttle plate clean it with carb & choke cleaner, our engines are old enough that this type of cleaner won't hurt anything.

Just caught something pretty important, you said when you changed the ignition components it runs good when cold yes? If so, did you coat the underside of the new ICM with die-electric silicone? You have to do that when installing a new ICM, it protects it from overheating, if you didn't and the car runs smooth when cold and goes to hell when it heats up, this is quite possibly the problem, as when you don't coat it, the ICM is fine at first, till things heat up, then you get issues.

 

The ICM came with the grease and I put all of it on the base of the distributor and the ICM itself.

I just mentioned that the additional load makes it want to stall or actually stall is because I was hoping it could help someone pinpoint the problem.

Fuel filter was changed recently, air filter is fairly new and I blew it out with some compressed air to get any debris out, oil was changed every summer since I got the car. I pulled the IAC and it was covered in carbon and the hole it goes into aswell. Tried cleaning that abit. When I pulled my sparkplugs few days ago they were covered in carbon too and also had some fuel on em (was cranking it alot and did not want to start for quite some time), wouldn't be surprised if the plenum is dirty too

 

You haven't seen dirty till you've seen the plenum up close and personal......

 

Code 44 for an '86 is Oxygen Sensor voltage. Get the $21 Denso Oxygen Sensor from Advance Auto Parts PN 234-1001. It should fix you up. I had the same problems, with the same trouble code. Replaced the O2 sensor, reset the ECM, and had no problems after that.

 

Does the car have this trouble when warmed up? In other words, can you hold the engine speed to about 1500-2000 RPM until the temp gauge (if you have one) registers that the engine is over 100*F indicated and have it run normal if you release the gas pedal? If it does, you need a MAF. And no, the engine won't always run with the MAF disconnected.

Your problem may either be the MAF or the oxygen sensor as said above. The oxygen sensor is cheaper (get the Bosch one instead of the Denso... it's OE), so try that first. If the new O2S doesn't work, I have a 3-month old AC/Delco MAF I'm willing to sell (can't use the digital MAF with the new system) that I bought new.