1997 2.3 auto, idle rough, sputter on accel

[Kayakfisher]

Recently got a 97 auto with 150k. Bunch of new parts put in before I bought it including: alt, radiator, front shocks, battery, muffler. Seems like new plugs, or at least wires, as they are red. Still has an exhaust leak after the cat where it connects with the spring bolts. I believe the gasket is shot.

Any way, it idles a bit rough at a stop, and when I accelerate it sputters for a second like it wants to stall, then goes fine.

Things I've checked;
Cleaned throttle body
cleaned IAC
cleaned maf sensor
spray check for vacuum leaks
Unplugged egr

No difference in anything.

Before I go blindly replacing parts and dumping into a hole, anyone have any suggestions on what I should check?

There is no check engine light.

No idea where to go from here. I did some research on forums and the things I've read are what I've done. Thanks

 

[tomw]

I would check that the fuel pressure regulator works. It will 'bump' the fuel pressure when you open the throttle. The MAF will also affect how the engine performs on acceleration. A moldy MAF will not tell the computer that the air flow has increased[quick increase], and will fail to add extra fuel to make up for the 'catch up' time a liquid will need to catch the air flow. The FPR does something similar, raising the pressure, and thus adding more fuel.
tom

 

[Kayakfisher]

I would check that the fuel pressure regulator works. It will 'bump' the fuel pressure when you open the throttle. The MAF will also affect how the engine performs on acceleration. A moldy MAF will not tell the computer that the air flow has increased[quick increase], and will fail to add extra fuel to make up for the 'catch up' time a liquid will need to catch the air flow. The FPR does something similar, raising the pressure, and thus adding more fuel.
tom

How would I go about checking that the FPR works?

Also, an update; I fixed the exhaust leak at the connection from the cat pipe to the muffler pipe, the flange with the spring bolts. They were completely rusted I had to cut them off, replaced the bolts and that lead gasket, which was awful. No leak there anymore, BUT I found another after this one was done. It's at the connection from the header to the cat pipe. A bolt on the flange is TOTALLY rotted and not even connected to anything anymore.

I'm bringing it to a exhaust shop tomorrow, should be a quick fix for them. I only have basic tools and a dremel, so it makes everything a long fix.

Would a leak before the cat cause my idle and sputtering problem?

 

[unrevealeddrive]

a leak before that cat probably wouldn't cause that unless it had a second 02 sensor downstream from the cat. have you pulled the plugs to check them. also even if wires look new they could still be bad. to check the FRP you pull the vacuum line off and see if there is fuel in it. there shouldn't be any there. probably should check fuel pressure should be between 35 at idle and 45 at WOT.

 

[Kayakfisher]

a leak before that cat probably wouldn't cause that unless it had a second 02 sensor downstream from the cat. have you pulled the plugs to check them. also even if wires look new they could still be bad. to check the FRP you pull the vacuum line off and see if there is fuel in it. there shouldn't be any there. probably should check fuel pressure should be between 35 at idle and 45 at WOT.

Hey so I got the exhaust leak fixed, and a new cat. Of course there was a hole in that as well, there always seems to be a hole in a cat when I get a leak checked. Anyway, sounds a lot better but there's still a slight hesitation/sputter. Not as noticable now tho that it's quiet with no leak. I'll check what I can from home, but Ill have to hold off on parts til next month probably now that I had to get a new cat $$