Check Engine light comes on only at heavy load

Hi Geo folks. I belong to the Nova forum, however, due to gas prices, just picked up an 88 Chevy Sprint as a work transportation car. I paid all of $50 for it. It has sat in a back yard for over 3 years, collecting a ton of water inside. It's all cleaned up and smells like a car now, however, now for the actual problem.

The Check Engine light comes on at full throttle, even in netural. While driving, it comes on, during load at about more than half throttle. I have looked for where the connector is to get trouble codes, but so far have not found it. When the light is on, it does feel like it's holding back a bit and could be delivering more power, even for 3 starved squirles. Since I come from an older V8 background without ECM computers, I am a bit lost. Any help, points in the right direction, location of where to get trouble codes, etc. would be appriciated very much.
Thanks

I've got an 86 Sprint and the check engine light is set to come at 30,000 mile intervals (30,60,90K etc...) regardless of whether anything is wrong or not. There is a slide switch just to the right of the fuse block that you simply move from one side to the other and it turns the light off until the next 30K miles have passed (I assume yours will be the same). Our cars are OBDI so they use the check engine light to flash trouble codes. Reset your ECU (by sliding the switch) then watch for the light, if it shows up again then you can read the codes and see what it's telling you (to read the codes you turn the key to on but don't start the engine and count the number of times the check engine light flashes). Also I don't think there is any connector for a scanner.
With your V8 background your squirrels will likely feel like they are holding back even when running in top form. I should mention that mine feels like it pulls strongly up through about 1/2 to 2/3 throttle and then noticably slows, it's done this since day 1. Do be sure to run some fuel drier/cleaner through the system after it having sat for so long. I've had good luck with HEET and Seafoam.
Also clean out your EGR valve and the passages in the intake manifold they get clogged and dramatically affect the performance of the the squirrels.

if a sprint is like my 94 metro

you go to the fuse box, and put a fuse in the empty slot that is raised higher than the other ones. the code will flash through the check engine light.

my metro gets a code only at freeway speed only for a second, and it claims its oxygen sensor. might be the same with yours sounds similar but still different though as well.

um a chevy sprint ok... weighs more than my metro and has less horsepower, and is carbed for lower throttle response.

Ive never driven one but Id say that is the slowest thing on the road. I mean it would still win a race with one of those old bugs but its in the same neighborhood.

what actually suprised me about my metro is the gearing is set so low it has a reasonable 0-30 time. Its still slow though, my other car is a mazda protege 1.5 litre and its night and day. and beyond 30 it gets real slow.

Thank you very much for the reply. I'll try the switch slide and see if I get any codes. You could be right about my expectations of power. It threw me when the light only comes on about half throttle (about where you can feel with your foot, the secondary barrel opening)

With the age and the car sitting that long it's quite possible the O2 sensor has expired (they are advertised as a maintenance item) but I hate to throw parts at a vehicle unless I know it needs them. Don't get me wrong I like it to run right I just hate to subsidize the parts industry unecessarily. As far as your expectation of power: You can get used to it if you give yourself a chance. You can drive by the gas station instead of into it; you can park in just over 1/2 a normal parking space (very handy at crowded events); typically insurance costs significantly less and you can use the money you would have otherwise spent for far more fun things. I thoroughly enjoy comparing my monthly owning/operating costs to the guys at work who have brand new trucks with $500+ per month payments, and insurance and fuel. Awe inspring power: no, chick magnet: no, super plush; no but I smile all the way to the bank.