5.0 problems

Clean your MAF sensor if you have one.... Check your tps and iac. Injectors might be crapping out cause that's good fuel pressure and timing. sitting that long a lot is gonna need cleaned up

What were the actual codes?

Did you install platinum spark plugs? They, a failing TFI, and a failing coil can all cause issues like you experience (amongst others).

Good luck.

If it sat since 01 then there is a good chance the injecters could need cleaning also, sounds like the fresh fuel loosened up some old after that 2000 mi you put on it.

white 89 GT said:

If it sat since 01 then there is a good chance the injecters could need cleaning also, sounds like the fresh fuel loosened up some old after that 2000 mi you put on it.

Click to expand...

My thoughts exactly!!!

Thermactor forces air into the cats, it's on the passenger side

Code 81 – Secondary Air Injection Diverter Solenoid failure AM2. The solenoid valve located on the back side of the passenger side wheel well is not functional. Possible bad wiring, bad connections, missing or defective solenoid valve. Check the solenoid valve for +12 volts at the Red wire and look for the Lt Green/Black wire to switch from +12 volts to 1 volt or less. The computer controls the valve by providing a ground path on the LT Green/Black wire for the solenoid valve.

With the with the ignition on, look for 12 volts on the red wire on the solenoid connector. No 12 volts and you have wiring problems.

With the engine running, stick a safety pin in the LT Green/Black wire for the solenoid valve & ground it. That should turn the solenoid on and cause air to flow out the port that goes to the pipe connected to the cats. If it doesn't, the valve is bad. If it does cause the airflow to switch, the computer or wiring going to the computer is not signaling the solenoid valve to open.

Putting the computer into self test mode will cause the solenoid valve to toggle. If you listen carefully, you may hear it change states.



Code 95 Key On, Engine not Running - the following test path is for 86-90 model Mustangs.

The 95 code is because at one time or another, the fuel pump relay hiccupped and didn't provide power the pump when the computer told it to run. Sometimes this is a one time thing, other times it is a no run or runs poorly condition.

Suspect items are bad fuel pump relay, corrosion in the fuel pump relay socket, inertia switch, wiring damage , corroded connector contacts.



Using the diagram, check the red/black wire from the fuel pump relay: you should see 12 volts or so. If not, check the inertia switch: on a hatch it is on the driver’s side by the taillight. Look for a black rubber plug that pops out: if you don't find it, then loosen up the plastic trim. Check for voltage on both sides of the switch. If there is voltage on both sides, then check the Pink/black wire on the fuel pump relay: it is the power feed to the fuel pump. No voltage there, check the Orange/Lt blue wire, it is the power feed to the fuel pump relay & has a fuse link in it. If there is good voltage there & at the Pink/black wire, swap the relay.

Some Mass Air conversions neglect to run the extra fuel pump wire, and they always have a 95 code. See MAF - Mustang Mass Air Conversion - StangNet - The Mustang Network for more information on the Mass Air wiring conversion.


Clearing the codes:
Codes may be cleared by disconnecting the code reader or test jumper once they start to dump. Alternately, you can disconnect the battery negative cable for 10 minutes. If you replaced a sensor, this is the recommended way to clear the codes since it erases the computers learned settings. However, the car may run poorly until the computer relearns the correct settings. This normally takes anywhere from 10-20 minutes. Clearing the codes does not fix the problem that causes them to set in the first place. It just enables you to troubleshoot things and then check to see if what you did fixed the problem.


Problems in the Thermactor Air System would not cause the symptoms you are experiencing. You either have a marginal TFI or a fuel pump electrical problem. Of the two possible causes, a bad TFI is most likely since the problem seems to get worse as the engine warms up

forget the IAC and TPS at this point Check out what jrichker says in his post.

Sorry for the thread hijack, but I was wondering why it is bad to run platinum plugs in a NA mustang? I thought they were only bad with forced induction. What symptoms do platinums exhibit?