Need help asap please.

[dieseldoc]

Ok my 94 base model start running bad yesterday. Low rpm at ideal and missing. I pulled it in and turned off the garage lights and it looked like a fireworks show under the hood. i replace all the plugs and wires and gaskets for everything i took apart. That helped, but still not right. I get a number 25 code now. Barametrics pressure sensor. I can't find it anywhere. is there anouther name for it? or is there something else wrong? please help. It's my only car and i need to get it running in a short. thanks for any help on this.

[Igovert500]

The barometric pressure sensor is in the MAS itself, check your MAS to make sure it was properly plugged in, clear, no clogging to the intake or damage to the honeycombs

if that all checks out, try unplugging and see how the car runs.

Which plugs did you put in and what were they gapped to?

How many miles on your car, and has it recieved the 60k/120k tuneup if necessary?

What rpms are you warm idling at?

Did you check your timing?

Last but certainly not least, check for vacuum leaks, in the hoses and the plenum. I wasn't quite sure if you go the problem before you changed the plugs and gaskets or after, but if after, make sure your plenum is seated properly and not leaking.

[sLADe781]

Not to sound stupid but how did you pull the codes on your '94 base? Because I have a '94 SL and have no idea how I can pull codes because isn't the only available scanner the OBDII? The '94 & '95 GTs use some type of hybrid scanner or something, right? Hmm....let me know how you did it please.

[dieseldoc]

Thanks for the help, everything checks out kosher. i think it maybe the o2 sensor on the exhaust pipe. anyone know what we can take off of the exhaust system and still have proper back pressure? i want to remove the cats and resonators. can i? thanks again.

[Stealthee]

Originally Posted by sLADe781

Not to sound stupid but how did you pull the codes on your '94 base? Because I have a '94 SL and have no idea how I can pull codes because isn't the only available scanner the OBDII? The '94 & '95 GTs use some type of hybrid scanner or something, right? Hmm....let me know how you did it please.

Shiver offers a logger for hybrids but if you jusrt want to pull codes search 3si for the paper clip method. It will flash your codes out at you via the CEL itself.

[2old]

I doubt it's a problem with the 02 sensor... If that fails the engines goes into a default mode where it actually idles a little high and the engine code would have indecated 02 sensor failure.

You could have a exhaust leak that plays havoc with the cars computer though...

Also, you don't need backpressure... The objective of the a good exhaust is to increase exhaust velocity while reducing exhaust pressure. Do a search, I am sure this topic has been covered before.

[Polygon]

Originally Posted by 2old

Also, you don't need backpressure... The objective of the a good exhaust is to increase exhaust velocity while reducing exhaust pressure. Do a search, I am sure this topic has been covered before.

Yeah, I can post a good article from SCC about it. Once the exhaust gasses have left the manifold they all the inertia they need.

[Igovert500]

CELs don't mean bad o2 sensors. If one went bad, that would throw a code of it's own.

When the barometric sensor in your MAS goes, the car acts as if you are at sea level. If you aren't, then obviously it isn't going to be running the correct air/fuel ratios, and cause your car to run poorly. Borrow somebody's MAS swap it in, it takes only a few seconds, and see if it fixes it.

Also, you said everything checks out, but you didn't really answer any of my questions...