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IronOutlaw
08-14-2009, 01:54 PM
Ok, Im trying to help my buddy get his car fixed. He brought it to a mechanic (http://mustangforums.com/forum/4-6-modular-mustang/556468-weird-problems-no-crank-sometimes.html#) and they cant seem to find out whats wrong with it but "fixed" some other things that ended up being over $400.

Its a 99 GT automatic. Sometimes for no apparent reason the car decides not to crank. Starter turns over fine, fuel pump (http://mustangforums.com/forum/4-6-modular-mustang/556468-weird-problems-no-crank-sometimes.html#) kicks on (I havent checked fuel pressure yet), but I think its getting fuel (http://mustangforums.com/forum/4-6-modular-mustang/556468-weird-problems-no-crank-sometimes.html#) due to the smoke it pumps out after it finally cranks.
Its not throwing any codes. I assume its not getting spark.

When the car finally cranks, which sometimes you have to wait for over an hour for it to, it revs up to 1500 rpms and then back down over and over (The AC is not on when it does this). Then if you put it into reverse it dies and doesnt want to crank again...put it in drive it will pull away and run fine. It runs perfect going down the road and is as fast as a stock 4.6 can be.

Mechanic wants to replace the PCM and the coil pack which is gonna be big money. Anyone have any ideas or had something like this happen before?


Also, another problem he has is sometime when going down the road in OD it will just start revving freely like in neautral, he has to put it in neutral and then back into drive to make it go again. Sound like a linkage problem?

IronOutlaw
08-14-2009, 01:54 PM
oops, I copied this from mustangforums and it moved the links to.

hotrod96z28
08-14-2009, 02:21 PM
Ponies are for little girls

Tbird232ci
08-14-2009, 05:46 PM
Ponies are for little girls
This has to be the least productive post. Even took the effort to make it bold.

It does sound as if there is a coil issue. My father Lincoln used to have an intermittent miss when he had coil issues. Does it have a miss?

Also, does once it's running, does it have any other issues?

Fastbird
08-14-2009, 06:01 PM
I trust the ignition switch has been verified to be good?

IronOutlaw
08-14-2009, 06:14 PM
Ok, the mechanic verified the ignition switch and key is good. They also said it shouldnt have anything to do with anti theft because that kills everything, not allowing the motor to turn over with the starter.


Tbird, the car doesnt have a miss, once its going it runs fine, just idles kinda weird like it has a vacuum leak and tried to die sometimes.

sinSStr
08-16-2009, 09:06 PM
Prolly not a coil. Look for a vacuum leak. 4.6s are known for intake leaks.

IronOutlaw
08-17-2009, 10:21 PM
Shop replaced the intake manifold and it made no difference in how it ran. I think they just go by hunches and dont have proper equipment to diagnose this thing, so its better for us to guess than pay them 100 bucks an hour to. Basically next time it dont crank we are gonna just tap on the IAC and see if it changes it. I gotta hunch that is what it is. The mustang forums has a sticky for them and my aunts explorer did the same exact thing until she replaced it, but you could tap on it to get the car to crank.

SexyTransAm
08-17-2009, 11:24 PM
here ya go have him look at this
http://i136.photobucket.com/albums/q170/SexyTransAm/8561802_l-1.jpg

96LT1355Z28
08-19-2009, 05:43 AM
Ponies are for little girls


here ya go have him look at this
http://i136.photobucket.com/albums/q170/SexyTransAm/8561802_l-1.jpg

^^^Really, come on guys this isn't LS1tech!:jest:

The IAC could create your idle issue but I don't see it being related to the the trans problem. I'm kinda confused by your post does it crank and not start or does it not crank as in starter not spinning the engine? The trans in that should be all computer controlled, I'm not sure if there is any linkage. If there is it doesn't ususlly just go bad unless he's been off roading in it! I'd check the IAC like you said and also look for vaccum leaks.

IronOutlaw
08-19-2009, 07:25 PM
I know the trans issue is unrelated just wondering if anyone has had that happen in any car for the matter.

Motor cranks but doesnt start. Starter spins fine just doesnt get any spark at all. I still havent messed with the car as it is an intermittent problem but I believe it to be the IAC.