5.0 manual...stalls when coming to a stop or quick deceleration...also rough idle...

[killer5.0]

had this problem for since a bought the car a few months ago...ive done some searching and reading but alot of ppl are having problems with it stalling while idling...my idle just goes up and down and sometimes drops out until its warm...but even when warm when i decelerate quickly or come to a stop 9 out of 10 times it will stall and its embarrassing plus annoying. here is a quick list of mods (all done b4 i bought the car so i may be missing a few i dont know about yet)

gt40 upper and lower
f303 cam
underdrive pulleys
200a alternator (i put in)
bbk fender mounted air intake
70mm throttle body
70mm MAF
bbk fuel pressure regulator
bbk shorties
straights to borlas dumped just b4 rear axle
short shifter
3.73

i know it needs a speedo gear since im off about 12mph...i bought the one i need but haven't put it in yet...was wondering if that would mess with the VSS?

any help would be great...
thanks

 

[liljoe07]

Do you have a VSS code stored?

I would run the codes and see whats up.

 

[killer5.0]

i need a tool to run the codes i presume? i dont have one...i guess my mechanic could do it

 

[Georgia306]

Clean your idle air controller with carb cleaner or just get a new one. They get dirty and make your idle do what you are explaining. My 92 did the same thing and I had to get a new one. Hope this helps

Chris

 

[killer5.0]

okay thanks....ill try it

 

[HISSIN50]

Agreed with Joe.

In your searching, I'm sure you've seen information about retrieving codes or buying a 30 dollar code reader.

Good luck.

 

[killer5.0]

30 dollar reader? i always thought they were a few hundred dollars...where can i get one?

 

[liljoe07]

Do a search for "surging idle checklist". You will find that you dont need to spend any money on a code reader. A test light and paper clip will get you the codes.

 

[killer5.0]

cool ill check it out

 

[frankeeski]

X2 on the VSS (Vehicle Speed Sensor). The speedometer works off the mechanical part of it and the computer gets it's reading from the electronic part of it. It will do exactly what you are describing if it has stopped working or is working intermittently. Note that the speedometer will still work so don't discount this as a cause.

 

[629RWHPstang]

i had the same thing and was just a small vacume leak

 

[killer5.0]

where is the vss located?

 

[liljoe07]

It hooks to the speedo cable on the side of the trans.

Just run the codes and it will tell you if you have a VSS issue.

 

[stykthyn]

sounds like a vacuum leak or really crappy timing. that code reader is a life saver. I got mine off ebay for 20 shipped and it has a digital display so I dont have to count blinking lights.

 

[killer5.0]

is it any code reader or ones specific to fords/domestics?

 

[liljoe07]

If you MUST buy a code reader, just get the OBD1 code scanner.

 

[killer5.0]

i found this one.... http://cgi.ebay.com/ebaymotors/Equu...Z370307833896QQptZMotorsQ5fAutomotiveQ5fTools

ok ill check out the obd1 thanks

 

[HISSIN50]

A code scanner is not useful on an aero fox. A reader like the one listed is all that's needed.

I like that reader because it's easier than counting flashes. It's frustrating to help someone fix their car when incorrect codes are reported because the flashes were not counted correctly.

A 3145 has an LCD screen if you'd prefer.

 

[Mustang5L5]

Can't beleive this hasn't been asked, but what year is this car?? Is it a converted SD to MAF car? Or is it an 89+ that has always been MAF?

#1 suspect to me would be the VSS, but if it's a converted SD car without cruise control, then it won't have one and this is a good probability why it stalls out.

Second guess if the VSS checks out is that you have a small vac leak int he brake booster or elsewhere.

 

[killer5.0]

sorry my bad...its a 1993 5.0 GT