Hi all, I have car with a no-start issue.Sorry for the long post but I think a little history is needed to explain what has been going on: We have a 2001 Taurus SE (3.0, OHV) that stopped working one day a few months ago. No sound coming from the fuel door when the key was turned to on indicated that the fuel pump went out. Got a new pump & had a mobile mechanic come & change pump motor (he changed out just the pump motor-not the whole sending unit). Car started & ran fine after repair. Then had same mobile mechanic change out the A/C fan clutch pulley out (dropped sub-frame & changed pulley though wheel well). Again the car ran fine after the repair. Let the car sit a few weeks and then decided to start car again to check trans fluid level. The battery was completely dead by this time so we had to jump it with another car. The Taurus started & ran fine but tranny fluid bubbled out of the trans fluid filler tube while I was looking at fluid level on trans fluid dipstick. Shut car off immediately. Car sat for a few more weeks until I found info on the AX4S vent cap being pushed down/blocked that would cause the bubbling trans fluid out of filler tube. Found tranny vent and cleaned vent & replaced the cap. Tried to start car but battery still dead. Jumped battery & car would turn over but would not catch. Sprayed starting fluid up the intake & car would catch & run for a moment & then die. Kept spraying short bursts of starting fluid & car would run for a few more moments, but it would run rough (pop & backfire) then die. Changed out the fuel filter & no change: car would still start, and still run rough (popping & backfiring) and still would die after a few moments. Called another (different) mobile mechanic and two guys came out. We jump started the car (battery still dead/won’t hold a charge) when the 2 mechanics got here. Car would catch, run really rough (pops & backfiring) for a few moments & then die. They pulled codes & said it showed codes P1131 & P1151. Mechanic said that usually means O2 sensor codes, but could be a bunch of different things. Mechanics looked for any missing or broken vacuum hose or tube & couldn't find anything wrong. Then they checked for broken or disconnected electrical connector & found no trouble found. Mechanics checked the fuses & relays & said they are ok. Mechanic got fuel to come out of the schraeder valve so we know the fuel pump is working. They checked both O2 sensors on top & cleaned the O2 sensor closed to the front of the car. The mechanics said there is a 3rd O2 sensor & they checked to see if it was hooked up & it looked OK. They cleaned the MAF, and the IAC sensor. After all this, the car will start (jumping the battery) and will run rough (some popping/backfiring) for a minute or 2, and then die. Mobile mechanics spent almost 3 hours and couldn't get the car fixed or really even isolate the exact trouble. By the end though, we were able to get it to start/catch & run on its own for a few moments without having to spray the starter fluid. Their best guess is that the car catalytic converter or exhaust is clogged/blocked, or that the O2 sensors are bad, or that one or more of the fuel injectors went bad. Kind of bothers me they didn't check the fuel pressure on a gauge and that the code reader they had was a bottom of the line reader & could do little more than read the codes. I just don't understand how the car could run great after the fuel pump & a/c fan clutch pulley change, but now be having this trouble. My gut tells me the trouble is something simple, that maybe I knocked off a vacuum line or broke a wire when I was looking for the tranny vent cap, but the two mechanics said everything is where it should be. In thinking over the problem last night I wondered if the fact that the battery is completely dead, and has been for some time, if that may have caused an issue with the PATS anti-theft system?? Since we can get it to start & run briefly (usually with starter fluid), I am not sure if that eliminates the PATS system? We have been using the key FOB to unlock the car and have been using the correct ignition key, but we have not put the actual car key in the door lock and manually unlocked it. Does anyone know if this could be the issue? I can't afford to spend money swapping parts out trying to find the trouble but I am going to buy a new battery for the car tonight at Costco and check my hunch. Does anyone know if the fact that the battery is and has been completely dead, if that will require a trip to a dealer to reset something (after I install the battery)? Sorry for the long post but I wanted to make sure I gave all the pertinent info. This has been very frustrating and I appreciate everyone's help & advice.

 

In regard to the PAT system, you should have a second coded key. If so, many problems are caused by coded key problems and it would be a good idea to try the second key.
If that solves the problem you cannot code another key without 2 good coded keys. Before going any further let us know if that corrects the problem.