Transmission/Idle problem. (Video)

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SleeperMark

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Hi guys. I have been searching for a fix to this problem since I bought the car. I have bought part after part with no avail. I have replaced upper and lower intake manifold gaskets, throttle body gasket, IAC and IAC gasket 2x, egr gasket, rubber T on throttle body, Cleaned throttle body and made sure it was shutting all the way, PCV hose elbow and valve, cleaned MAF at least 20x, converted tranny to Mercon V and replaced 1-2 shift accumulator and springs. None of these helped. I forgot to mention in the video that the tranny always wants to upshift early causing the car to bog out really bad but if tou just tap the brake it downshifts to the correct gear. It also always feels like you are a little on the gas until you come to a complete stop. Thank for the help. I cant imagine how happy I will be to get this fixed!!! :rolleyes:

Here are the links to my videos. Thanks in advance

IMG_0039.MOV - YouTube

IMG 0040 - YouTube
 
1) Check your vacuum lines, you may have a leak somewhere and it's affecting drivability. Regarding the hanging idle when the car is moving in neutral, that's actually pretty common, even with all the 5-speed Mustangs I've had (95+ GT's). It helps with drivability as well as with pollution control (keep the engine from giving off too much unburnt gases during decelerations)
2) did you change the swaybar end links?
 
I have checked all the lines I can see and they are all fine. I have not changed the sway bar end links, but they seemed tight when I had them off to do the LCA's. They're cheap enough that I may give them a shot
 
I can hear what sounds like a small vac leak coming from behind the engine... Any lines ack there that I am overlooking? I replaced the EVAP line coming from the T into fender, and the AC line that goes into the firewall. Do the PFE hoses have a high failure rate maybe?
 
Sway bar links, could be the actual sway bar bushings or upper control arm bushing. You may also want to check the rear upper shock mounts, that's exactly what they sound like.
I went through several IAC valves before I got a good one. I didn't see the tps listed and as for the vacume lines... How did you check them? Visually or spay them with starting fluid or carb cleaner? On the a gen 2 there are vacuum lines going to the egr control behind the motor, no fun to get to.
 
Visual and sprayed vac lines with carb cleaner. The TPS has been replaced 3x. As I was tracing lines I felt the 2 silicon tubes for the PFE to EGR and they feel and look fine. (used a mirror to see them). Here's the other weird thing. With the IAC disconnected the car runs EXACTLY the same. The idle doesn't drop and try to die out like it should. If i disconnect the vac line from crankcase to intake tube the idle has minimal change, if i disconnect the vac line for the PCV the idle has moderate change, and if i disconnect the vac line for the brake booster the car lopes really bad but keeps running. Weird that the one on the intake doesnt make a bigger difference than the PCV with the hole being 4x as big... Car is confused, haha
 
Also, while I was disconnecting all those vac lines... the IAC was disconnected. I was literally TRYING to get the car to die and it would not...
 
maybe a diff problen with TPS tho. It was replaced 3x because when i started the car the RPM would shoot to 2500 and not go down. Replaced TPS and it was fine. But this happened 3 times within a few months... kinda weird odds to get 3 bad ones in a row. Will the car idle with the TPS disconnected? Maybe I can start with finding why I have that hanging idle. And where SHOULD the idle be? I have seen anywhere between 500-800. Mine varies from 900-1000
 
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SleeperMark said:
maybe a diff problen with TPS tho. It was replaced 3x because when i started the car the RPM would shoot to 2500 and not go down. Replaced TPS and it was fine. But this happened 3 times within a few months... kinda weird odds to get 3 bad ones in a row. Will the car idle with the TPS disconnected? Maybe I can start with finding why I have that hanging idle. And where SHOULD the idle bee? I have seen anywhere between 500-800. Mine varies from 900-1000
Click to expand...

Mine idles around 700 to 800. Really haven't paid much attention but the 94 I had was having a weird idle and after swapping out the TPS and IAC, the problem was fixed and yes, if the TPS is left disconnected, it will idle but it's not going to idle like it should. If the TPS came from AZ, it is possible to get two or three bad ones right out of the box but I have no clue where you got them.
 
maybe ill just buy a motorcraft TPS and see what happens. As far as the transmission thing I was talking about where the idle is at 1,300 until a complete stop while in neutral. Does yours do that also? It feels like there is always throttle while i am braking.
 
Forgot to mention a possibly important part. I cleaned the throttle body with carb cleaner (yes being ignorant and ignoring the sticker). The hanging idle was always there, but ever since then the idle has been around 800-1,000. when i got the car the idle was at 600. not sure if that matters but i figures i would throw it out there
 
SleeperMark said:
Forgot to mention a possibly important part. I cleaned the throttle body with carb cleaner (yes being ignorant and ignoring the sticker). The hanging idle was always there, but ever since then the idle has been around 800-1,000. when i got the car the idle was at 600. not sure if that matters but i figures i would throw it out there
Click to expand...

Mine idles around 500 to 600 smooth as glass, As for the "clunking" sound, mine did same thing. Replaced UCA's (cause bushings were bad) and it got better, replaced stabilizer bar end link's and it continued getting better (that was more of a rattle tho), replaced upper shock mounts (sounds just like yours) and I was almost there, replaced rear shocks (also sounds just like yours) and ......no more noise.
I believe it was a combination of all 4.
UCA's and end links clunck were coming from front, upper shock mounts and shocks were coming from back.
No mistaking were they were coming from.
Everything looked good and felt good except for booties were gone and no more grease.
 
Spree, I just replaced front and rear shock mounts and it helped but the clunk is still there. UCA's and sway bar endlinks will be next. Thanks for sharing your experience. Any ideas about my idle?
 
SleeperMark said:
Spree, I just replaced front and rear shock mounts and it helped but the clunk is still there. UCA's and sway bar endlinks will be next. Thanks for sharing your experience. Any ideas about my idle?
Click to expand...
UCA's...if you can move them from front to back and see the (bushing's) move, they need replaced.
End link's I couldn't tell until I removed them but they rattled all the time (and were very loose when car was jacked up and pressure was taken off the spindle), yours sound like a clunk but hard to tell from a vid, LCA's also clunk.
As far as the idle goes...I'd definitely check all the little VAC lines as I've learned. Someone (GMAN) pointed out a VAC leak I had and since then I must have tracked 50 feet of FREAK'N Vac hose just to see if any more were broke! Mine caused my defroster to freak out. Wish I could help out more with the idle but I know some else that has more EXP with that will chime in soon...
 
SleeperMark said:
Spree, I just replaced front and rear shock mounts and it helped but the clunk is still there. UCA's and sway bar endlinks will be next. Thanks for sharing your experience. Any ideas about my idle?
Click to expand...

If you UCA's or sway bar end link's look like these.....replace them! I'm more of an (suspension expert) and not so much on the engine as I've not had any engine problems YET!

Front Stabilizer Bar End Link.jpg


Front Upper Control Arm.jpg
 
chris2523 said:
mine looked like that. made a hell of a racket.
Click to expand...

My sway bar end links rattled (wasn't a clunk tho) all the time....drove me nuts but the new ones looked nothing like these, the new ones had bigger connecting rod, bigger ball joints and were bent almost like an "S".
 
Spree said:
My sway bar end links rattled (wasn't a clunk tho) all the time....drove me nuts but the new ones looked nothing like these, the new ones had bigger connecting rod, bigger ball joints and were bent almost like an "S".
Click to expand...

yeah the Moog ones are bent. i used TRW ones, they were straight like the ones i took out.
 
SleeperMark said:
I can hear what sounds like a small vac leak coming from behind the engine... Any lines ack there that I am overlooking? I replaced the EVAP line coming from the T into fender, and the AC line that goes into the firewall. Do the PFE hoses have a high failure rate maybe?
Click to expand...

Here's my two cents:

Hanging idle = vacuum leak MANY times, that is the case and MANY times that was my case with the countless vehicles I have owned.

You really need to look over every nook and cranny of your upper intake/vacuum lines. If you have an AUDIBLE leak, I would suggest flicking the throttle while your head is under the hood and see if you can determine a ballpark location where it is coming from. I'm not certain if the throttle body design is the same on your Gen1, but on the Gen2s there is a "plug" on the underside of the throttle body with an o-ring. That plug happened to simply work its way out of my throttle body and all of a sudden I had a pinky finger sized vacuum leak. (What I would consider a biggie). We found it laying in the valley under the intake when we tried to address the problem by replacing intake gaskets. Was this an oddity to me? Yes. But oddly enough, another member had the same problem and he told me what this random plug was that I found because it happened to him!

I don't look at "failure rates" per say when it comes to situations like this. You need to have a mental approach that anything might happen. I've had a few anomalies with my car where people say, "how the hell did that happen?". Can those hoses DPFE hoses fail? I would say yes they certainly can. Anything from dry rot to potential leaks from softening up due to underhood engine/exhaust temperatures.

Another thing to consider is that sometimes vacuum lines can develop a leak that is more of a "dimple" in the line when throttle is applied. You may look over your lines when the car is idling and all seems well until throttle is applied and vacuum is pulled through the line and exposes a weak spot in the line which is actually a pinhole that has already developed.

Not trying to complicate this whole thing. Just giving you some insight. Good luck! ;)
 
That's what I would go with.....check all VAC lines again and again, it's gotta be there somewhere!
 
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