Hi all! I have a 2001 Max SE automatic with a tad over 108,000 miles on it. Sitting at Burger King lastnight, the SES light comes on. Went and had the code pulled. P0172. Says Fuel System Rich Bank 1. Probable cause: High Fuel Pressure, Leaking Injector or pressure regulator, OR Maf Sensor Fault. Came on here to check things out. Read up and then got confused because of conflicting information. Some of the threads talk about cleaning/replacing my MAF and others say the O2 Sensor is bad. I can't afford to replace anything at all, let alone all of it, so I need to figure out what it is. If an O2 is bad, will I break down on the road? I actually bought this car to replace my van which the timing belt keeps breaking even after idler and pulley replacements. I broke down THREE times with my kids this summer, so I went and bought this car. I'm very nervous though because as it turns out there are a zillion things wrong with the car and I dont even know where to start. I wont allow any noise while I am driving so I can listen to this thing, LOL! I know I sound crazy, but you stand on the side of the road three times with your two kids and no cell phone to call for help, then every little sound you hear a car make will give you panic attacks, trust me

Anyhow, I can't really tell you if the car is running sluggish because I don't think it had any original power when I bought it five months ago. It has a bad strut on front drivers side, two bad motor mounts, I dont think the previous owner EVER changed the oil, probably ran 87 el cheapo octane gas in it, as a matter of fact, I dont think they ever did a darned thing to the car but destroy it. I did just put a different gas in it the other day, I normally run Amoco Ultimate or Chevron's 93 octane in it, but the other day I put in Exxons 93.

One thing I can tell you, and I dont know if it means anything, but I can be sitting in park, rev her up to 2-2500 rpms, then let off the gas and it drops way down to almost stalling then picks herself back up again. I honestly dont think I've EVER gotten her past 3000 rpms because frankly, I'm scared to death to give this car a good drive just yet. I'm planning to figure out what's wrong with my van, get it back on the road in the spring, then take this off the road and rebuild it. But right now, am I safe to keep driving, or, is she gonna break down on me? Can I drive another week or so with a bad MAF or O2 sensor? I know power and mileage will be affected but I dont have any money to replace either part, and I dont have a way to get my kids around.

I know, lots of chatter, I'm a talkative gal and I have so many questions about my poor broken car. So, for now I need to know if I can drive it with those issues, which one of the issues would I be looking at, O2 or MAF, or, could it be the fuel injector, how do I know which one, or pressure regulator? Lastly, I do get the rotten egg smell, oddly enough, it came on really strong one day, the car wouldn't get over 20 MPH with a HORRIBLE miss, we headed for the cat but it was an ignition coil. Go figure. It has thrown the CAT code, but, then it just disappeared, no light was on and now, it's not throwing that code, just the P0172.

I thank you all for any help you might have for me. Have a great one! Pamela

 

Because the P0172 code has such varying possible causes, I can't say to change a part with a 100% guarantee. You've described a lot of symptoms that kind of sounds like a MAF. But not 100%. There is a thermistor inside the MAF that can be cleaned and will fix a MAF problem. But not always.

The car may be running in what we call "limp" mode. With certain problems, the car computer backs down the engine performance and people will complain of sluggish performance. Supposedly the engine rpm will not go over 2,500 but I had a bad MAF and was running in limp mode and I could get up to 4,000 rpm. One thing I noticed was that the transmission would take a long time to decide to shift.

Can you drive the car with a bad O2 sensor or MAF? Yes. People will drive with a bad O2 sensor for months. Same with a MAF but maybe not as long because of the poor performance. But if you start smelling the rotten eggs, that is not good because that is the catalytic converter overheating which means the engine is not burning the gasoline all the way. If this happens, I would avoid driving the car as much as possible.

 

I'm going to see if someone will clean my sensor for me and see how that goes. Now, the rotten egg smell, is this a BAD Cat, or is it just not working properly due to something else? About two months ago the rotten egg smell arrived. It's very intermittent now, but, this one day the car was in terrible shape. It had a severe miss as my husband put it. Basically, floored, she wouldn't go over 20. Had to force her home, I got tired of paying 75 dollar tow bills to get my vehicle two blocks, when I had my van. So, we get her home, but that smell, WOW!! It was horrible strong, I mean, BIG TIME!! Automatically went for the cat. Cant afford a 600 part at the moment, so hubby beat it up, or whatever he did, I dont know, I didn't watch, LOL! For whatever reason on the planet he decided to OHM everything. Ok, so car wont go, we got the smell. What did we find? A bad ignition coil! Replaced it and all was right in my world again. Except, yeah, we still get the smell here and there.

Now, pardon me but I live in a very redneck town. I'm not from here, but it's where I live. Lots of guys keep telling me to take the car to this one guy who will remove the cats and run a straight pipe. I am told it's illegal, but we dont have emissions here, and apparently I'll be ok in the legal part. This guy actually is a shop, a muffler shop. Pay him cash, he'll take it off and put the pipe on. Question I have is, will this car run that way?? I mean, we have O2 sensors and such, so, will the car operate without all that telling it what to do or what? Seems all the big boys with the big trucks, get by just fine. But I'm driving little Maxi, and she seems a bit temperamental after being severely neglected and abused by the what I will assume was a man that owned her before me. I will say man cuz he tore her apart to put in a stereo system, there were grease stains on various parts of her interior, her oil looks like a sludge factory, even her hood struts are broken. The poor thing. I know she's gonna require a few grand, but she has to wait a minute while I go deal with Uncle Sam and the IRS and whatever it is they think they are doing to me from last year's taxes. So, what do y'all think? Can I run a straight pipe temporarily, THEN when I have the thousand dollars, put a nice exhaust system on her? Or am I stuck with straight pipe (IF I can even do that) if I wanted to change later?

I have a zillion questions, maybe I'll start a new thread for some of them so we dont get all off track here

Thanks for the help! Cross your fingers and pray for me! I need that MAF cleaning to help things, or other than that, I am at a loss for what to do for the poor gal until I can pay for it.

 

a catalytic converter has platinum coated pellets that somehow causes the unburned gasoline hydrocarbons in the exhaust gasses to be burned. This makes the catalytic converter get hot. If there is too much unburned hydrocarbons in the exhaust gas, the catalytic converter gets a lot hotter from burning all the extra hydocarbons and you get the smell. Eventually a catalytic converter is "used up", it can only burn up so many hydrocarbons. When a catalytic converter reaches the end of its life, it loses its ability to let the exhaust gas pass through it and we say it is plugged up - because it is.

O2 sensors are like a mechanical nose sniffing for unburned hydrocarbons. If one of the O2 sensors "smells"
hydrocarbons, it snitches to the car computer and the computer waves a red flag in your face, the check engine light. That's all that happens. If you have a bad O2 sensor or you decide to take them all out and throw them away, all you get is a red light on the dash, nothing else.

A plugged catalytic converter prevents the engine from running. If the engine can't get the used exhaust gas out of a cylinder, it can't get any fresh fuel mixture in so the engine can run.

I'm thinking 2 things. 1 - the engine is still running too rich as you still get the smell from the catalytic converter. Maybe the MAF is causing it, maybe there is another bad ignition coil. 2 - the catalytic converter is starting to plug up and this is causing the poor performance.

A car will run just fine without a catalytic converter, in fact, a little better than with it. And if the catalytic converter is plugged, the car will run a whole lot better. If you remove the catalytic converter, I think an oxygen sensor (O2) gets removed also. This means you will have a check engine light that you will not be able to reset (turn off). There is a "modification" that someone figured out where you get a resistor and add it into the wire harness in place of the O2 sensor so you don't get the check engine light.

If you were to get the catalytic converter removed, I bet your car would run better. Your car still has problems, but it would be a drivable car with problems.