Well... I finally got enough time off work and a dry spell in the weather, and I dropped the tank and replaced the strainer, pump, and filter.

The good news? My car starts easier, idles well, and the pump is much quieter than the original one I pulled out.

The bad news? Instead of bogging down at 1200 rpm, it now bogs down at 2500 rpm. Definitely not drivable, but there is quite a bit of improvement. When it bogs down and I let up slightly on the throttle, the idle smooths out and stays running (which it wouldn't do before), so the fuel pump was definitely partly to blame.

So now what? I've gotten the advice of a friend and he suggested checking vacuum. I plan on getting a gauge so I can take a look at it, and I have a sneaking suspicion that I might have a partially clogged cat/muffler. If I had the money and time, I'd just keep throwing parts into it until the issue goes away; sadly, I can't afford to...

Anyone have additional ideas I could check? I know the car has had the ignition module replaced twice in the past, and also had a coil pack replaced. The plastic timing gears have already been replaced under the TSB for metal ones, and a new timing chain was installed too, at under 100,000 miles. I'm still not getting the SES light, even if I hold the throttle steady when it'* bogging down.

Thanks for your help all along, and for future help. I feel like I'm banging my head against the wall here, I'm usually really good at 80s GM diagnosis.

Your best bet is more diagnostics. I think you should check the fuel pressure just to rule out fuel delivery issues. If you think it is exhaust restriction (clogged cat), you can disconnect the down-pipe (if the rust lets you, that is) from the rest of the exhaust system, and then take a rock around the block. If there is an exhaust issue, the car will drive fine (albeit loud ).

I'll be kinda miffed if everyone tells me to check fuel pressure, and I blow the $60 for a gauge (half a paycheck, BTW), and it turns out to not be the problem.

Or you could do Loan-a-tool:

Great Neck/Fuel pump diagnostic kit (27167) | Fuel Pump Diagnostic Kit | AutoZone.com

Or harbor freight:

Fuel Pressure Tester & Fuel Injection Pump Tester

Yeah... I thought about the loaner tool thing, but the local stores stopped doing it even though Corporate has ads all over our local TV stations bragging about it. The stores claim they never get the tools back (hence the deposit - which is often twice the retail price of the tool) and once I had to beg - and beg - and beg, to have a loaner seal puller. LOL...

I figure the Craptron/Actron vacuum gauge at AZ/AA I'll purchase, since all cars have vacuum lines, it'* a worthwhile investment. A few years ago I bought a fuel pressure gauge (back when they were <$30), loaned it to my boss' then-boyfriend, and then my boss had her Splaturn hauled to the junkyard - with my gauge still connected to the fuel rail. Gee, thanks. Haven't thought about replacing it until they went up to $70, and the $70 one isn't as nice as my $30 one was. *shrugs*

Meh, time to get ready for work... Getting the vacuum gauge tomorrow (unless the website is wrong and they don't have it in stock - or they have it in stock in a bin somewhere for over two months and never shelved it, AA did that to me once with an 18" piece of straight exhaust pipe, I had to order it and they had ordered them so many times they couldn't fit them all on the shelf!)

Can't believe they give such deplorable customer service, and will never hire people with actual knowledge... *smh* I should open my own place. LOL

people who know what they are doing would want more money than they pay im sure.

Bear with me, I'm typing this on my phone. lol

I just did a vacuum check on the car, since it'* almost 50 degrees outside. (Although my car is stuck behind a 3-foot-high snow pile, so road testing isn't an option yet)... I have a nice strong 18-20 in Hg of vacuum at 2000 rpm, and it doesn't fluctuate or decrease in Park/Neutral. However, putting it in Drive or Reverse drops my vacuum to 4-2 in Hg. and it starts to bog down. Am I looking at something directly or indirectly related to the transmission itself? The tranny was replaced under factory warranty just before 75k even though it didn't fail - one of the previous owners had a son/grandson that worked at a Buick dealership. So the brand new tranny has 52k roughly on it. Should I turn my attention to the vacuum solenoid on the front of the tranny? Or is it something else entirely?

I should say that I connected the vacuum gauge to the filter/tee thingy that feeds the EGR solenoid and HVAC. In the process, I broke one of the connectors on the tee, so obviously I need to replace that.

I'm usually awesome at diagnosis, especially with OBD-I GMs... But I'm completely self-taught and definitely stumped on this one...

Maybe I'll just splurge for the OBD-I to Serial interface cable and use that old Pentium 1 laptop I've got collecting dust, just for data logging to see what the heck is going wrong. Although I love driving Mom'* Intrigue (it used to be mine, lol), the poor girl has 197k and I don't feel comfortable with only one running car in the family with that kind of mileage. Plus, my radio is better. lol

Totally random brainstorm just hit me... Could it be the TCC solenoid? Doubt it would work that way, as my '88 Cutlass Ciera and Mom'* old car ('87 Pontiac 6000 */E) acted differently, having to get to top gear first... But different trannies, on the 2.8 MultiPort.

plug the line on the engine to the trans and see if it acts differently. it could just be something else. try plugging other things this way too. if you whatever you broke leaks vacuum be sure to fix that first