engine loss of power

[saturn]

Shelly, '82 Rab conv, has developed a major engine loss-of-power/hestation/misfire/sluggish problem when its been running for about an hour. The hot weather (100's) in ca's central valley was a contributing factor last weekend when she almost left me high and dry on the side of the freeway. She'll be goin' along fine @ 60, then start bucking when I hit the gas, then slows down to 45, which is hard to maintain, then slows to crawl, sometimes it stays idling, mostly the engine just quits. She'll start-up after 3-4 min. of waiting. I first noticed this problem 2 months ago while cruising @ 65, it went away after 10-20 seconds, but now its a lot worse. I'm trying to narrow the cause down between the many thing's it could be. I'm thinking it has a lot to do w/fuel delivery because it only seems to happen when she's under acceleration load, even a slight increase will set it off, back off the throttle, and it goes away. The Bentley bible notes that an incorrect warm pressure setting on the control pressure regulator can cause similar symptoms (haven't tested this yet, don't have a CIS pressure guage) it also mentions the fuel distributor (lifted the air flow sensor up and down, no rough movement noticed). It could also be the ignition coil, I've had similar misfire problem, replacing the coil helped. I haven't done much to fix this problem, except prepared for a complete tune-up as Shelly does still run (like shit tho), just not on the freeway.

Anyone have any experience w/this type of problem? And where does one get a new control pressure requlator? My parts place says Bosch doesn't even make them anymore, they said go to pick-n-pull. Any advice, helpful or otherwise, is welcome.

Thanks!

[CalAltaDubber]

I tend to agree with your fuel system assesment.

When I was in Europe a few years ago, I had a similar problem with the car I had there.

It turned out to be a badly contaminated fuel tank. When we drained the tank, the gasoline was black!

Had to drop the tank, clean it out, and re install. It took a couple of weeks and fuel filters before all the crap in the fuel lines made its way through. Of course a tune up was required to finish the job. (plugs were filthy).

After that it ran great until I sold it.

[gull]

Get the CIS gauge and check the pressures before you start looking for a CPR. You'll save money in the long run. JC Whitney sells a decent CIS gauge set for $60.

CPR is one possibility, but an hour seems kind of long for a CPR problem. I would expect it to show up as soon as the engine fully warmed up.

Have you changed the fuel filter?

I had an intermittent stalling problem that showed up only when I was stuck in stop-and-go traffic for a long time. I chased it round and round for a while, thinking it was an ignition problem. The car would also hesitate during hard cornering if the fuel level was below 1/2 tank. It turned out to be the in-tank fuel pump. Eventually it just failed entirely one day and the engine wouldn't keep running, so I replaced it, and so far no more stalling. Dunno if that's your problem or not, but it's certainly a possibility.

[saturn]

Installed new fuel pump, Shelly has some more power now. We'll see how it goes, I'm not convinced enuf that the problem won't resurface some time in the future, but for now so far so good. I was glad the eng. didn't need much cranking to get it going, the fuel accumulator must have had fuel in reserve. Thanks for advising the pump, it was making a lot of noise prior to going out, the old one looked oem, after 25 yrs, replacement should be expected I guess..