Not necessarily. Some vac leaks (intake manifold, throttle body gasket) may throw misfire codes or lean codes -- but not always

Spray throttle body cleaner around the intake manifold, with particular attention to cyl 1 (channeling Keith).
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As for knowingly putting the wrong plugs in your Saturn, then driving it around, and experiencing driveability issues which, based on your description, now includes driving on 3 cyls with the wrong plugs.......don't know what to say. Other than that I drove my 97 SC2 on 3 cyls for 9 months on the right plugs, and now I have some idea of which vibe you mean.

But come on, us helping you diagnose and solve some types of driveability issues is next to impossible if you don't stick to the basics......you're pissed about people who don't maintain their cars, but you knowingly put the wrong plugs in your own?
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Is the exhaust sound smooth or do you hear misses?

The car will of course idle higher in neutral than in gear, so either it's the drop in RPM in and of itself, or the fact that engine is now under load and when it tries to drop the idle to the PCM's predetermined range. It obviously can't because it keeps searching back and forth for am air/fuel amt and ratio that will work.

Hence Rube's comment about a vacuum leak. The PCM only knows about the metered air; if there is additional, it will lean out the mix based on front O2, read lean on the front O2, which in turn triggers an overrichening of the mix, because it is accounting for the overly lean condition resulting from the combo of what should be there + vac leak air.

So the idle just bounces back and forth hunting for the air/fuel mix that will settle it down---but there IS NONE---so on it goes......

This likely does not happen in Neutral b/c the amnts of fuel and metered air are larger, and assuming the intake manifold is not the culprit, the added air contribution from the vac leak is fixed or increases at a slower rate such that its contribution to the overall air/fuel mix is either not significant OR the PCM is able to figure out a mix that provides a stable idle.

I suspect it to be a small vac leak based on the above

Throttle body gasket is a possibility, as is the line from the PCV to the air intake ducting.
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The TAAT4 A/T in the S cars either have the input shaft nut come loose, pressure control solenoids go bad, other shift solenoids go bad......

The easiest way to attack this is to install a reman valve body, since all solenoids should be functional and in spec plus if you only replace a few solenoids now, you'll be pissed when you have to take it apart to replace the others. Check the condition of your tranny fluid and decide whether or not to change it. Unless it has been in there a very long time, I would change it. Flushes cause more harm than good---just drain and replace,

THEN take it out for a drive and see if the shifting is smoother.

And congrats on becoming a permanent fixture here, Bang.
We're here to help each other.

 

"As for knowingly putting the wrong plugs in your Saturn, then driving it around, and experiencing driveability issues which, based on your description, now includes driving on 3 cyls with the wrong plugs.......don't know what to say. Other than that I drove my 97 SC2 on 3 cyls for 9 months on the right plugs, and now I have some idea of which vibe you mean.

But come on, us helping you diagnose and solve some types of driveability issues is next to impossible if you don't stick to the basics......you're pissed about people who don't maintain their cars, but you knowingly put the wrong plugs in your own?"

- Well, I do admit that was somewhat of a contradiction on my part, it honestly ran better for the 20 minutes that 1 plug was in there.


- Alright, well now I got 5 new solenoids.

" since all solenoids should be functional and in spec plus if you only replace a few solenoids now," -------- I completely agree with you on that. No one likes a half-*** job.


Thanks for the tips though! I just spent 2 hours inspecting everything that could cause a vacuum leak.. When you mentioned the TB. I recently did remove it, installed new gasket of course but I probably got a leak there for sure....

Before I did my intake gasket the car didn't run as rough as it does now....

ALSO it is possible Debris from gutting the precat fell into the exhaust line, I had it positioned out of the way the whole time, a few slips here and there but that's all it takes... I could've messed that up as well.

Damn, well, I'll get this done and post results.

Thanks!

 

You're quite welcome.

And thank you for not getting all defensive. I wasn't trying to be an *** -- just sticking to the facts and trying to help. Alot of people that came before you have loaded a double barrel, blasted at me and the forum, and then were banned or just vanished.

The gift of accepting constructive criticism is not that common.

You'll fit in here just fine, Banger.

 

Lol, thanks.

So, here's an update. Change the solenoids, no change at all what so ever...

Here's my question, the fuel filter, fuel line. Is it possible there's air trapped in there? I'm not sure how the fuel system works, i'm not proficient in that area.

Would a clogged fuel filter cause these symptoms? hell, even a pump?

One thing I did notice, it smelled rich as hell when I started it up..

I'm losing my marbles here

 

car runs in open loop mode when starting from a cold sart, and you can smell the rich mixture being used until the idle stats to come down as the PCM starts listening to all of the sensors that are now supposedly giving valid readings. Once he PCM is happy w the readings being not bogus it goes into closed loop mode, where the air/fuel mix is determined by the A/F mix, the front O2, and the ECTS reading.

When you replaced the ECTS, did you go OEM or aftermarket? And did you replace the connector?

Remove the connector and look for signs of leaked coolant and green buildup. Corrosion here can reek havoc with the ects reading.

Highly recommend going with OEM ECTS + connector (dealer only). $45 ieh. At least the connector if there are any signs ofcorrosion

 

Yeah, I discovered the hard way that the little squeeze connector on the ECTS can be cracked pretty easily. If that happens, then the connection is loose and can really mess with things. Be sure to solder the new connector in (not just wrap it with tape) and then use heat shrink and THEN tape if you like.