I need help on my 98 Mustang, again!?

Question

well here i go again. car works fine until it gets hot, once it gets hot, you can step on the excelerator and it wont go, it just stumbles and on occasion it sounds like it back fires. ok i replaced the maf but still no dice. i got trouble codes po171,po174,p1151,p1131. i dont have a proper airfilter on there just one i fastend from an f150. i already changed out the fuel filter and in the process of changing out the tps. also when you unplugg the maf, it buys you a little time before it stumbles again, this happened on with the new sensor as well. this is very puzzling and have yet to find a solution. i really hope someone out there can help. thanx in advance

Answer 1

change out the 02 sensor. check in the haynes book, it will operate in open loop mode until the manifold turns 600 degrees at which point it will start sending readings, this will cause for it to send messages to the injectors to not send enough gas.

Answer 2

the p1131(bank 1) and p1151 (bank 2) is the o2's detecting rich, for a lean condition. the p0171 (bank 1) and p0174 (bank 2) detects lean.
you have a vacum leak somewhere after the maf. either the maf isn't sealed, the air tube isn't sealed to the throtle body, or you have a gasket leak, most likely a leaking intake gasket. do not replace the o2 sensors. get rid of the p0171 and p0174 and see if any others codes come up after


H41 DTCs P0172, P0171, P0174 AND P0175: FUEL SYSTEM AT THE CORRECTED FUEL TRIM
Diagnostic Trouble Codes (DTCs) P0171 bank 1 (Cylinder 1) and DTC P0174 bank 2 indicate the fuel/air ratio is too lean. The fuel trim system is at the rich correction limit.

DTC P0172 bank 1 and DTC P0175 bank 2 indicate the fuel/air ratio is too rich. The fuel trim system is at the lean correction limit.

DTCs HO2S Reference list:

HO2S-11 = DTCs P0171 and P0172
HO2S-21 = DTCs P0174 and P0175
Possible causes:

Fuel system

Excessive fuel pressure.
Leaking fuel injector(s).
Leaking fuel pressure regulator.
Low fuel pressure or running out of fuel.
Contaminated fuel injector(s).
Vapor management valve (VMV) leaking.
Induction system

Air leaks after the MAF.
Vacuum leaks (vacuum lines and gaskets).
Restricted air inlet.
PCV system.
Fuel purge system.
Improperly seated engine oil dipstick.
EGR System

leaking gasket.
Stuck open EGR valve.
Leaking diaphragm.
Base engine

Oil overfill.
Cam timing.
Cylinder compression.
Exhaust leaks before or near the HO2S(s).
Check intake air system for leaks, obstructions and damage.
Check air cleaner element, air cleaner housing for blockage.
Verify integrity of the PCV system.
Check for vacuum leaks.

Answer 3

Not real sure but i think the air filter needs to be correct for the system. Don`t know what the codes are , and it would help us help you to know what the are. Hope you get a better answer.
Have fun today.

Answer 4

Change the o2 sensor

Answer 5

be sure all small wires on battery side of solenoid are solid & clean. ford uses a dedicated ground for computer, small black wire hooked directly to battery negative. be sure all are clean and tight.