Help! i dont want my 01 nissan to die

[InsomniaManiac]

Apologies everyone,after reading and then registering then reading again, i came to find this isnt a website that specifically helps with car engine issues, but i thought it woulndt hurt to ask.

problem: 01 nissan sentra automatic
symptoms started as choking up engine roughness and dying while traveling at highway speeds, took it to local mechanic, diagnosed it with mixture rich problem, MAF sensor not responding, they did back pressure check and found the precat had been clogged due to unburned fuel etc, they quoted my 2,200 for a new cat a new precat, o2 sensors, i think it was six of them, MAF sensor.
to which i responded thats worth more than the car!!! they are good people and understood my situation, i payed their diagnose fee and towed it home( because now it wouldnt run)

AT home i chopped off the rusted screws binding the cat to the precat pipe,... started the engine and again she would start and died (sounded cool tho)so next step, buy some cheap headers from ebay with no cat and see if that would at least let the engine breathe and start.....
two painful days later(so much rusted screws) i got the new stainless steel headers installed with the o2 sensor foulers i discovered in this website and a new mass airflow sensor,.... started it, she turned over but then quickly died,... started it again, this time i gave it some gas, she turned over with erratic rpm and then settled at about 900rpm,... i screamed with joy,.. but then it it turned into tears of sadness as i pressed down the gas pedal and discovered it didnt want to go past 2000rpm.

i only drove it around the block to see if she would at least drive,she never went past 25mph,.... i dont want to take it back to the mechanic shop, but iam out of options if its another problem.

comments,suggestions,questions and ideas are welcomed

[Bob Smith]

Here are 2 relatively cheap suggestions:
1. Might be your fuel line filter. Typically, the sediment will settle in a filter, but once the gas gets flowing, it clogs (especially if it's old and has a lot of sediment). Mine would do this after a few minutes on the road - chug, chug, die; wait a few minutes and start, move then chug, chug, die...
2. Might be your fuel pump. It depends on the kind of pump (and where it's located might affect price). One of my old cars would start then immediately die because the diaphragms in the pump were torn. Pumps can be cheap, but they can also be expensive if they are inside the gas tank.

I'd say check these 2 items out - might save you a few bucks.
Bob

[charly2]

There are several problems with your car, the 2000rpm problem is due low fuel pressure, the computer will try to compensate the lack of fuel without success, a new pump will fix it for sure.
Now the MAF will fail very easy if the alternator is not working properly, turn the main front lights on and see if they blink (not stable intensity), if the do it repair the alternator first, it can make the computer blink and fail too at any speed, then replace the maf if is necessary.
Do not change the maf before check the alternator, it will not last long.
I had a 2001 std sentra, same symptoms, and the diagnose will make most experts crazy before they find the root problem.
Hope this help.

[ewizard]

Get an OBD II tool. You can get Bluetooth OBD II off eBay for $13 or so. The bluetooth ones tend to give you more info than some standalone tools. You of course need a laptop or smartphone that has bluetooth to see the info. See what areas are giving error codes. Clogged CAT's will make things run terrible. I think some one said to replace fuel filter - that can be a big problem it it's way dirty or has water in it. You might have gotten some bad gas. You'll probably get a lot more answers on an auto forum and probably look for a Nissan forum. I've found some excellent help on car specific forums.

[Bob Smith]

BTW, re the MAF sensor -- You can get MAF sensor spray that does a pretty good job of cleaning it. I know my older Toyota MAF needs a cleaning every 6 months or so. The engine light generally goes on with a dirty MAF. After I clean mine, I remove the appropriate fuse to reset things so the light goes off. Maybe someone else can comment here. If it's still functioning but dirty, it's worth cleaning - an import MAF sensor is expensive.