[Michamike]

Just adding this info in because it may help solve my problem. A month or so ago I posted how my check engine light comes on and my rpm gauge jumps all over the plays. Even though the gauge jumps, it does not effect the true idle of the car. Now my car starts up fine goes to idle around 800 to 1000 then drops to 500 or lower. At that point it ether stays idling around 500 or just dies. Car will start right back up after it dies. If i feather the pedal and keep the rpms around 800 for 5 minutes and let go off the gas the car will idle fine or if I drive it for a few minutes it does the same thing. The only changes i have done to this car lately is that the day before the idle problem start witch was this last Friday. Is that I disconnected my negative cable to hook up a new socket for the light under the hood. I also put on a new clutch cable. I did a full tune up about a year ago and I have only put 5000 miles on it scenes then. I am bout to just take it down to the Ford dealer and have them run an engine diagnostic if i can't get this fixed over Thanksgiving week end.

Thank you for any help

 

[PhoenixSheriden]

search either the site itself, or search my threads for how to pull codes. its easy to do yourself and it will save you a c-note at the ford dealer. even if you buy your own code reader you will save yourself money, theyre only $25-30 at the parts stores.

since you dont have codes yet, its more guesswork, but the likely suspects would be the maf, idle air control, or possibly icm.

however you get the codes, post em up when you get them. but also let us know what parts you replaced as part of the tuneup.

 

[turboeeyore]

try spraying some intake cleaner in the throttle body, removing the air inlet at the throttle body, then start the car and rev'er up a bit till the motor smooths out.may have to do this once or twice but try using the whole can in 2 part sessions. should clean out the iac.

 

[Michamike]

Sorry for the late replay PhoenixSheriden I haven't gotten the codes off of it yet. Going to by a code reader later today. For the tune up I put new spark plug wires, new belts, new egr valve, new fuel filter, new K&N air filter in, new spark plugs (was told gap to be set at .044), and I cleaned out the throttle body and idle control valve too. In facted I just cleaned out the throttle body about 200 to 300 miles ago. Not sure if I did a good enough job if it is idling like this now. Should also add that my gas mileage seems to be going down too.

 

[PhoenixSheriden]

i could be wrong, but doesnt 91 have a mass airflow sensor? a bad maf will just screw up everything. i'm also adding to my previous guesses-the throttle position sensor might have a bad spot in it.
since youre getting a code reader, obviously post codes when you have them. it always helps when someone pulls codes beacuse it cuts down on the ammount of troubleshooting work we have to have them do to find the problem. once we have codes we can pretty well tell you what you need to replace and why, since the computer has done all the component testing for you :winks. i love being able to pull codes rather than having to spend an extra hour in my unheated garage screwing with a volt meter to bench test half a dozen parts when something starts behaving badly in my stang.
and no worries on a late reply, we all understand that real life stuff happens and sometimes fixing the mustang must wait.:yup:

 

[Michamike]

I bought some specific cleaner for the mass air flow sensor and I will try that out. I was going to get the equus 3145 code reader for the fords but did not end up buying it. The guy at the store told me scenes the check engine light doesn't stay on all of the time I won't be able to pull codes off the computer if the check engine light is not on. The check engine light only comes on every so often when I am driving and shut off when I come to a stop. Kind of weird. He did offer at least one suggestion. Told me to check my heat sensors by the thermostat and exhaust manifold. Told me if one or both are bad that if could effect my RPMs and my gas millage will go down too. Any ideas on that.http://www.google.com/imgres?hl=en&...w=131&start=0&ndsp=52&ved=1t:429,r:0,s:0,i:86

 

[ranger50toy]

Store guy knows crap. You can get codes in memory without the check engine light on. They are intermittant problems.

 

[Michamike]

So i finaly got the code reader and all it would give me was ether 000 or 10. Damn connector and wires where so corroded that I had to cut, strip and put new connectors on the ends. Odd thing is when I did the first test the radiator fan turned on for a few seconds. Not sure if that happens you any of you guys. Should also add that I did the test a few more times after that and I only got code 10 on the first test. Maybe I am not doing it right. But I fallowed the instruction book on every set

 

[PhoenixSheriden]

the fan is supposed to cycle for a few seconds, its one of the things the computer is checking for the test.
are you positive that all youre getting is a code 10? I am pretty sure 91 should make 3 digit codes. and also theres no number 0 in codes. if you can, post up a vid of every single flash the code reader makes.
you should at least be getting a code 111 (for 3 digit years) or a code 11 (2 digit years). those are the system pass codes and if there are no problems then you will get that code.
the k &n filter could have screwed up or killed your mass airflow sensor. the oil on the k&n filters really wreaks havoc with the fillaments in the sensor. definitely use that maf specific cleaner you bought to clean it with. unscrew the maf from the housing (so you can get to the filament portion of the sensor) and unplug it from the wiring harness when you go to clean it.

 

[Michamike]

Positive that I go the 10, but it was only 1 time out of the 4 other tries. Other wise it always showed 000. I will check the wires again and make sure the connection is good. As i posted the wire harness was corroded and one of the wires was broke. So I had to put on new connectors. I don't like changing the wire harness but I didn't have much of a choice. When I get a chance I will post some picture and will try it again tomorrow.

 

[Michamike]

Ok. So i redid the connectors and even used a wire brush on the copper wire too. With the new ends I got a good enough connection to get codes of off the car. I got 111, a 10, and a 224. Ignore the 10, that number was just put in to separate 111, and 224. Sorry no video.
111 was from the O test, key on engine not running. The 224 is from test C witch is the continuous memory.