I just bought a 1990 IROC convertible with a 305 TPI, auto trans and 2.73 rear gear. I searched the forums for someone with similar issues but didn't really find any answers. I had 2 of these cars in high school but that was almost 30 years ago so I don't really remember how they drove. I am aware that the 305s were not really known for their power but I am certain there is something wrong with this one. The car sat a lot before I bought it. It only has 64k miles on it and the guy I bought it from almost never drove it. The tires were flat spotted from sitting. We trailered it home and when I took it out the first time I had a hard time keeping it running. It died a few times. I assumed it was from bad gas. It didn't have much gas left in it so I dumped a can of Lucas Oil injector cleaner and some Sea Foam in there and filled it up with 93. After that it ran much better and it seemed like the more I drove the better it ran. The issue remains that it has almost no power down low. It seems like when I get on it the car almost immediately shifts into second which makes it even more of a dog. It also doesn't want to down shift some of the time. Not sure if it is a power issue or a shifting issue but I am guessing it is mostly power related. Obviously this could be 100 things I am just looking for some areas to start looking at. Plugs, wires, injectors, etc... Any help is greatly appreciated!

 

I'd be looking at the TV cable for shifting issues. I wouldn't drive it much without verifying it's adjusted properly, you could burn up the trans with an improper setting. Generally speaking, it was unwise to drive the car after it had been sitting for a long time. The last thing you want is to pack your injectors full of varnished gas, but it sounds like you may have avoided that fate. I'd recommend changing filters and fluids soon, as well. If you plan on doing your own work, the factory shop manual is a very valuable asset.

 

Thanks very much for the info! I do know the oil was changed recently due to the receipt and window sticker that were in the car. I do plan to get it up on the lift soon and change the fuel filter and generally look things over. Probably change trans fluid and filter while I am under there. The previous owner did drive it but it had been several months since it was last driven.

 

Start with a compression test and a fuel pressure test, then proceed from there.

And as Komet already mentioned, make certain the TV cable is adjusted properly.

 

Adjusted the TV cable last night and it made a huge difference. The car was severely short shifting and it just had no get up because of that. I am sure there are other issues to address BUT that made a big improvement. It still doesn't seem to down shift correctly. When I slow down for a curve and then roll back into the throttle it stays in gear and doesn't back shift. This obviously causes it to be very doggy coming out of the curve. I plan to change the fluid and filter in the trans as I don't know when that was last done. That will give me an opportunity to look at the fluid for clutch material or dark fluid.

As suggested I will check compression and fuel pressure as well. I am sure there are plenty of threads on how to check fuel pressure. I have never done that before on an EFI motor. Guessing I will need to purchase a gauge of some sort as well.

 

Just keep in mind this a stock 305 with a 2.73 axle ratio. I'm not sure what expectations you have, but it's not going to be a screamer in any sense of the word.

 

when was the last time it was driven before you picked it up from sitting? fuel can get nasty. could have a clogged fuel line/filter/injector. thus that pressure test, although that wont find an injector that is mis-behaving. I wouldnt worry about the tranny shift quite yet, shift it manually if needed. but when you downshift into 2nd you should see some pep. is the engine able to run thru the RPM's while in park, or does it get rough at certain RPM's? Is it idling smooth, or choking on and off, rpm's fluctuating? did you check spark plugs to see if they are clean? did you make sure timing is where it needs to be? is distributor and rotor clean? may as well start finding the vacuum line diagrams, make sure all those lines are connected properly and in good condition.

 

Thanks very much for the info. The owner said he drove it once last summer. It has had a recent oil change and he said he "thinks" they installed new plugs. I fully intend to go through the ignition system completely and make sure everything is good. The engine revs clean and idles nicely now that I put fresh fuel and some Seafoam in it. I have not looked at vacuum lines yet. I do know it has the leak in the heater control like most do, so i will fix that.

 

Oh I know. I had 2 of these back in the day. I don't expect it to be a screamer by any means. It is just obvious there are some issues that need ironed out. Once I get it running right I do plan to change the rear gear as well.

 

if it were me, I'd just replace all the plugs, cap, rotor and fuel filter, check timing and make sure nothing at thru the spark plugs and vac hoses while it was sitting and change oil. can do all that for <100 bucks and get it out of the way. but thats just me....... even a brand new motor won't run good with bad ignition components.

 

Totally agree. I have all those components coming from Rock Auto as we speak. Thanks for the reply!