Power issues

I have a 93 pontiac sunbird. I have ran my actron code scanner, and it is saying code 34:

MASS airflow sensor-signal voltage or frequency is low during engine cruise.


MAP sensor-signal voltage is low during ingnition on.

I am not sure where to start, or which one to start with.

First off I dont know where they are on my car.

The problems that I am having are not having very much power when I accelerate, and losing power up hills.

We just put in new plugs, wires, a fuel filter, and air filter.

How do I locate the MAP and MASS sensors? Which one would be most likely the problem.

I do not have a tester, but if need be then I will purchase one.

Thanks in advance! Julie

The answer is at your local auto parts store. Just pick up a copy of a Haynes repair manual for about $20. Read it cover to cover. The manual has a lot of helpful pictures and a great wiring diagram for the entire vehicle in the back of the book. You can also register at autozone.com and use their helpful repair guides. I could tell you but that would be taking the fun out of maintaining and repairing your vehicle. Besides…I’m too lazy this morning to look it up.

Just Google “where is my Manifold Air pressure or Mass Air flow sensor” and your car type and you will find pictures and way more stuff than you can read in a couple of hours.

Julie, I want to thank you for your common sense, your willingness to find out, and your non-shyness about automotive work. You go girl.

I think what these guys are trying to tell you is that the Haynes manual will tell you how to test the Manifold Absolute Pressure Sensor and the Mass Airflow Sensor as well as their locations.

Hint: the MAP sensor will be on the intake manfold, the MAF sensor will in or just aft of the airbox with the air filter.

You might consider the possibility of a clogged catalytic converter. This could possibly cause MAF or MAP codes and could sure explain a large loss of power.

The best way to check for a clogged converter (and to generally determine what shape an engine is in) is to connect a vacuum gauge.
Vacuum gauges are cheap, connect in seconds, and will tell you a lot almost instantly.

The instructions that come with vacuum gauges can be a bit iffy as a clogged exhaust can cause any one of a number of readings; with much being determined by how severe the clog is.
Sometimes the instruction sheet makes it appear to be a one size fits all thing.

Oh, I dunno… Haynes pretty much sucks. Most problems I have aren’t addressed in the 3 Haynes manuals I have. They’re better than Chilton’s, but not by much.

Well, I use to know more about cars. When I was 16 and dating my now hubby, most of our time spent together was working on his 69 firebird.

I had a mild stroke when I was 29, I have had type 1 diabetes for over 36 years now, and I also have fibromyalgia.
Even though I am disabled, I am stubborn! I will do what I have to, to fix things that I know nothing about. I am sure non on you really wanted to know this, but my point is that I am a little slow sometimes, but I am a fighter. If something has to be done, then it has to be done. I try to learn what I can, even though I have forgotten a lot of stuff from my past experiences with cars. Also with absolutly no health ins, I have no choice but to fix things myself. I have not worked enough in my life to get disability. My hubby gets disability, but he worked for over 30 years. He rebuilt tractor and 18 wheeler clutches for a living, and the cleaning solvent cause him brain damage.

I really apprecate all the help I have gotten on this message board. It save me last month with my TCC solenoid.

I actually have a book on my car, but its so old and missing pages, and it has not helped that much.

But thanks again to all who have helped us out! I will pay it forward somehow!


What happens if I just remove the catalytic converter? My car does have 205.000 miles, so I am really not too worried about not having it.

Thanks, Julie

Never mind, I just realized that it is illegal to do that. I guess I will do some more research on cleaning one, and go that direction.

Hopefully that will be the problem and I can solve it. If not I will repost and go from here.

Thanks again, Julie

For $20 it’s the best repair manual out there. It covers most repairs but not all. I’ve spent far more on some manuals and have gotten far less.

You want to first determine if a part is defective before removing it anyway.

Hopefully next week I can have a friend of the family check it for me.

Thanks again for the advise! Hopefully this is the problem and I can have power again to my car.