Any ideas.

[Creepy847]

Today I go outside and warm up my 2003 SVT. Car starts fine and I walk back into the house. 5 min later I come out and as I walk up to the car it stalls out.

I fire her back up and notice right away that the speedo needle is going from 0 to 160 back and fourth.

I shut her down and restart. Same thing. The rpm needle is fine but the speedo is going from 0 to 160 back and fourth.

Again shut down and restart samething. I try to shift the car into reverse to back up and it wont shift over to reverse. Orignal stock tranny. Shut the car down again and try to shift the car into reverse. It shifts fine.

Also the car starts to stall after a min or two. I dont force it to run with applying throttle I let it die.

Now I start the car up again. Same thing crazy speedo needle and wont shift over to reverse or 6th. Feels like its blocked. Car finally stalls out again.

I check the Clutch and it feels good. I just replaced the clutch last year. Car is not driven hard either.

I start her back up and samething. Shut her down and I can then shift to reverse or 6th.

Now I get out of the car take a break. Come back out 10 min later and I start her up. All seems fine the speedo is where it suppose to be and I can shift into reverse or 6th.

Take the car out to my buddys shop. Run test and it comes back with no codes. I throw a new battery in her while Im there cause the battery is getting old.

Drive the car around after that for about an hour and have nomore issues.

I cant find much on it online so I thought I would ask you guys if anyone of you have ever seen anything like this.

Car seems rock solid and I havent had a single issue shifting into any gear or noise.

Yesterday I was out most of the day in the car and all was fine.

Like I said when I walked out today this all happened after I started it up.

So far its fine and its been afew hours. I did read somewhere that it could be a battery issue. Last week we did new spark plugs and required maintence and the cars been fine since.

So with that said if any of you gentleman can shed some light on this I would be greatful. I just dont wanna be driving it like this if theres something thats about to break and leave me on the side of the road if its something I can fix now.

Thanks and again sorry this was so long.

Creep847
2003 Cobra SVT
62,000

 

[32ValveRom]

Whoa, that's an issue I haven't heard of before. You may wanna try the 4.6 section for some additional help.

 

[Kilgore Trout]

Gauge sweep like that indicates loss of battery power, you were right to replace the battery. Most likely the problem is solved.

 

[Creepy847]

still not luck. Car is still doing same thing. Sometimes it seems okay then you drive it and you come to a stop and all the sudden youll see the speedo start to spike.

Then the car will stall. It starts right back up but as soon as you come to a stop it does the same thing.

Spent the weekend troubleshooting and came up with nothing. Maybe the speed sensor? Either way my brain is burned with this one. It has to be something electrical cause it comes and goes.

Im taking the car to the dealership today and let them fix it. Im still under warranty so I guess its best to leave it to the pros.

Ill post the results of what they find here. I really want to know what could cause this and will def share with the community.

Thanks for the replys and wish me luck.

Creeps.

 

[Kilgore Trout]

The stealership will figure it out, my guess is severe short or bad ground in electrical system or bad PCM.

 

[wmburns]

+1 on above. The battery is recently replaced, but are the terminals in good condition (clean and tight)? The ground lug is bad about splitting if over tightened. What about the battery cables?

The gauge sweep means power was lost. Each time power is lost, the PCM needs to re-learn fuel trim values. That is why it is stalling.

While in the dealership, check to see that the updated calibration to address the stalling problem has been installed (assuming no custom tune).

 

[Creepy847]

Well the dealership has the car now. Of course when I went out this morning she didnt give me a single problem. Its about a 20min drive to Tasca and the car didnt show any issues at all.

So when I got there I described what happen in detail and hopefully they'll be able to replicate the problem.

Since the car is still under warranty let them deal with it. I check the battery terminals and afew other things mentioned, but Im not a pro so I could have missed any number of things.

The car has a custom tune so the idle problem isnt something I thought about. Like I said before the car has never done this before.

Well they probably wont get to it till tommorow, but Ill def let you guys know what they say. Thanks again for the replys I really appreicate it alot.

Creeps.