Great I intend to keep driving it to and from work just over 2 miles a day. I do not have large keys with all kinds of stuff on it putting weight on the ignition. You guys are really helpful. Took it out today for a short ride.
A quick check of rockauto shows 2 MAF sensors for the GTS (4AGE motor) and one unspecified MAF sensor so unless you have a GTS, db4690 may be right. But if you do, it is in the intake duct just before the throttle body, easy to get at. The MAP sensor is at the end of the intake manifold and is also very easy to replace.
You need another mechanic. This one is feeding you BS.
I’m inclined to agree that you need a new mechanic.
A MAF (Mass AirFlow) sensor measures the total amount of air coming through the induction (air intake) system, and is located just behind the air filter box and before the throttle body.
A MAP (Manifold Absolute Pressure) sensor measures the absolute pressure (the pressure from absolute zero, or as measured against a total vacuum) in the intake manifold. Since it measures intake manifold pressure, it’s simply a pressure sensor screwed into the intake manifold. These along with the throttle position sensor, the engine speed sensor (could be on the crankshaft or the camshaft depending on the engine), and the temp sensor are the primary inputs to the ECU that determine the fuel metering (how much gas gets sprayed into the engine). The exhaust is then monitored by the upstream oxygen sensor and tweaked for optimum emissions.
Assuming your understanding of the mechanic’s statements is accurate, it sounds to me like he doesn’t even know what a MAF sensor or a MAP sensor is/are.
By the way, all engines with electronic fuel injection have one or the other, some but not all have both. If he were subscribing to a repair database like Alldata, Mitchells, or whatever, he should be able to look up the details for your car. If he’s not, you shouldn’t even be going there. These subscription databases are essential to a shop.
Having written all that, I’m inclined to agree with others here that the problem is in the ignition system. A good shop will be able to diagnose and correct it for you. Chances are that it will be far, far less that the prices this guy is quoting you.
The reason I don’t believe OP’s 1990 Corolla has a MAF sensor is as follows . . .
In all likelikhood, it probably doesn’t have the top of the line motor
My 1995 Corolla, which is the next generation, didn’t even have a MAF sensor, because it uses a speed density system, which is cheaper and less accurate than if it used a MAF sensor.
Therefore, I have a hard time believing your probably non-top of the line 1990 Corolla has one
I go to pick a part often, and there are always plenty of Corollas of OP’s generation there. Never have I seen that one of them have and/or had a MAF sensor
I’m really beginning to think this mechanic is grasping at straws . . . big time
Just what is this mysterious sensor that lurks deep inside the engine, and requires huge cash expenditures to replace . . . ?!
If OP gives this mechanic the authorization to repair the car, there’s a good chance the end result will be unhappiness all around. Lots of money spent, many parts unnecessarily replaced, and the car is still not fixed. And parts can’t be returned, because the boxes have been opened and the parts have been installed
I wholeheartedly agree. Hopefully the OP will go elsewhere.
I admit, however, to being puzzled at the mechanic’s statements… or perhaps if they’re being accurately restated. This stuff seems awfully basic for a mechanic not to know.
I will try and get more information from him tomorrow, maybe my husband is not understanding what he said ( very possible). Took the car out again and it stalled at the train station 2 blocks away and then restarted and stalled again as I was pulling into my driveway. I was not able to restart it the second time we had to push it into the driveway. Engine is just dead when it won’t restart. No noise nothing. I agree about another mechanic I just wonder if the newer mechanics just don’t know how to work on cars that don’t provide clear diagnostics with a flick of a switch. My daughters boyfriend offered to look it over, but it is really cold here in NY and not a great time to be outside working on a car. So it may have to wait a month or so.
I paid $100 for the car from a friend who was going to junk it simply because he did not know what to do with it and was moving in with his daughter and leaving the car behind. He was elderly and drove it to and from the supermarket. Over the years it has done its job for us taking both my kids to college.
Thing is I am a bit sentimental about the car, is that possible? My husband just wants to get rid of it but I feel like it might be worth the trouble to give it one more try.
How can you possibly be sentimental about a vehicle that could leave you stalled in front of a train?
This is the kind of problem that’s diagnosable and repairable if you can get it in the right hands. There are a lot of great young mechanics still coming online. They’re the ones who grew up driven by curiosity about how things work and willing to do the work to learn. Unfortunately, there are also some that became mechanics because they thought it sounded cool, and some of them are rather limited IMHO. I cannot think of a single field that doesn’t suffer with the same problem… even medicine. And there are a lot of great old-time mechanics out there too.
“Engine is just dead when it won’t restart. No noise nothing.”
So, no cranking! This changes everything. Forget all those sensors, you have a major electrical failure.
Not sure if it applies to 1990, but 1992 Corollas I think came w/ one of two possible engines. The base version (my own Corolla) uses a MAP. And the sportier version uses a MAF.
Mechanic said he is 99% sure it is the MAP sensor-- my husband looked this year 1990 corolla and all the other years it is an inexpensive part for this year for some reason it goes up in price. Where is it located is another thing–
Sentiment is purely personal-- people are sentimental about all sorts of things that don’t make sense-- to each he’s own 
Here is a link with a pic of your sensor locations. http://wheresmyiat.blogspot.com/2011/11/2003-2012-toyota-corolla-iat-sensormaf.html
On my 92 Corolla the MAP sensor is mounted on the firewall as per the link above, but on the driver’s side, not the passenger side. One clue if you are looking for it OP, there’s a sizeable diameter vacuum hose that goes from the map sensor to a fitting on the intake manifold.