I may be in the wrong place to ask the question, if so plse let me know.
I bought my 87 about 18 months ago and am really happy I finally upgraded from my Camaros! I find it usually cold starts on first try, but once warmed up is really hard to start. So last week I took it out for a good run. Put about 300 miles on it, the first 150 miles on it w no real issues (w the cruise on at about 55MPH, did not push the speed at all). Car sat for about 90 minutes, then on my rtn a real lack of power. On a stopped start I found nothing over 2500rpm and sluggish coming up my gears (auto trans). On the highway, was stuck behind a guy doing 35mph, pulled out to pass, and could not get over 40MPH. I'm not sure what was worse, failure to pass, or failure to pass in my vet. I had to pull off, waited a coupler of minutes and nursed it up to 55 (really soft steady acceleration). I've looked through the forum but did not find any posts that are identical to my challenge but from what I could figure out, I'm thinking, bad fuel filter(s), maybe the cats, MAF, dirty Fuel injectors or fuel pump. It sees the mechanic this week, but any ideas? (I'm no mechanic but do want to breathe some life back into the car. It has about 80K miles, and if I drive like a K car it is usually OK, but I want to try and make the name proud, keeping it original as best I can).
As an aside, I use the site regularly, just changed out some burnt out 882s on the dash. Easy fix, aqnd I only removed the face plate as recommended. The best source for vet info anywhere.
I'd post pics of the car but can't figure out how to load them.
Thanks again, Paul (Ottawa Canada)

 

naw..
Dead Kitty.

To be more specific, probably the 2 Pre-Cats. Those are corks and need to ..go away. It will pass most anyones smog test with only the main cat in place. Your miles are low but the age is high...cats die or plug from a variety of things. Age is one. Pre-cats dies because they are pieces of crap and GM eventually figured that out and stopped using the small pre-cat because they plugged and failed regularly. I think 87 was the last yr for pre-cats.

Get the fuel pressure test gauge to confirm. If you get 40 psi or close at key ON,...you're OK there.

Maf will get you a SES lite. So will ANY other sensor failure.

Plugged fuel filter starves the rails so you won;t see the 40 psi normal pressure. It takes 25+psi to build a fire in these...30 to make it run.

IF you had a plugged filter, it would backfire and cough. It woud try to die. It would be hard to restart until it sat for a few minutes..

Don;t overlook the air filter....it happens.

If it were spark..you;d be walking. Tha does not come & go. It also gets a lite.
There is a code for everything.....EXCEPT CATS & low/no fuel pressure.

Test the cats by removing the o2 sensor and starting the engine. IF there is pressure blowing out of the bung...thats your problem.
The max exhaust back pressure is only 2-3psi. That much or more indicates theres a dead cat in the driveay.

From what you describe, getting worse the farther you go, getting weak, no power, gutless,.etc, its due to get worse. So bad that it won;t rev past idle, so get the diagnosis done asap and get it to a muff shop asap...'cause you;re on borrowed time as it is. I've had it happen and barely made it to 25 mph and able to turn into a driveway at the shop. No backfiring, no coughing..just gutless and weak.

 

Replaced both Fuel filters (primary was OK, secondary was almost done) and the Fuel pump was on the low end of pressure. Replaced it all and now runs at 100%.

Thanks to all.