This is the stock tune. Stock tune shouldnt do that right?
It also does it on the AM email tunes I have.. along with the pinging which is why I run the stock tune for now till I need a dyno tune.
Trans issue or something else?
- Thread starter sarmikgar
- Start date
This is the stock tune. Stock tune shouldnt do that right?
It also does it on the AM email tunes I have.. along with the pinging which is why I run the stock tune for now till I need a dyno tune.
Got a chance to take the mechanic who did the prior work on the car for a test drive, seemed like a nice guy, said he worked at Ford dealer prior to this Chevy dealership, and owns 4 mustangs, one he said is "modified alot"..
Anyway, the rpms stalling out at 4k he said he couldnt reproduce when he drove it, but he saw it when I was driving and suggested having the cluster serviced/replaced
his reason was that the mph is still climbing so maybe the tach in the cluster itself is bad, so I asked "well why doesnt it do it in 1st gear?" and he said the computer is recieving differant signal or something and so is sending differant one to the cluster kinda sounded like a wild guess to me(I have 3 ase certs.).. but since he sees it, if the new cluster doesnt fix it, they now cant deny that there is an issue is the way I am looking at it.
He also heard the front end creaking, I tried to tell him I thought it was str. rack bushings(if you get down on ground in front of car and have someone crank the whell back and forth its pretty obvious its the str. rack or the str. rack bushings), and he sorta agreed, but also recommended replacing something "struts" and "upper and lower" I am unsure what parts he was talking about exactly. I forgot to mention the tsb.
I told him the codes could be a vacuum leak, and he said he would expect it to idle badly if it were vacuum leaks.
Car is going back to dealer on Tues. next week. Will have about 800-1k miles left on warranty at that time probably.
Any more help very much appreciated with this.
Anyway, the rpms stalling out at 4k he said he couldnt reproduce when he drove it, but he saw it when I was driving and suggested having the cluster serviced/replaced
his reason was that the mph is still climbing so maybe the tach in the cluster itself is bad, so I asked "well why doesnt it do it in 1st gear?" and he said the computer is recieving differant signal or something and so is sending differant one to the cluster kinda sounded like a wild guess to me(I have 3 ase certs.).. but since he sees it, if the new cluster doesnt fix it, they now cant deny that there is an issue is the way I am looking at it. He also heard the front end creaking, I tried to tell him I thought it was str. rack bushings(if you get down on ground in front of car and have someone crank the whell back and forth its pretty obvious its the str. rack or the str. rack bushings), and he sorta agreed, but also recommended replacing something "struts" and "upper and lower" I am unsure what parts he was talking about exactly. I forgot to mention the tsb.
I told him the codes could be a vacuum leak, and he said he would expect it to idle badly if it were vacuum leaks.
Car is going back to dealer on Tues. next week. Will have about 800-1k miles left on warranty at that time probably.
Any more help very much appreciated with this.
wmburns
SN Certified Technician
If I close my eyes and JUST listen to the engine, I can not detect any decrease in RPM's. If you watch the speedometer carefully there is NO hesitation in it's movement (even through the hang point).
The tach does hang at 4k. Again, if the tach was accurate, then there would be a change in engine pitch at the 4k point. There is not. Further, the speedo would also stop accelerating when the RPM's stopped increasing (it does not).
Further, when driving the car, do you FEEL the acceleration hang at that point? Forget for a moment what the tach says because if the tach were accurate there is no way you would not feel the change in acceleration.
I agree with the mechanic. The problem is in the cluster. Note, the 1999-2004 cluster gets speed and RPM's as an electronic signal from the PCM. For proof, use your SCT and monitor/datalog RPM and speed.. Reproduce the problem. Graph the results. If the RPM curve is smooth, this PROVES it is in the cluster. If the RPM curve shows a hump at 4k, but the MPH is smooth, this means we have a mystery to solve.
As to why it does not happen in 1st gear, maybe because in 1st gear everything is climbing faster. Perhaps the momentum of the needle movement carries it past the "hang" point. In the other gears, the acceleration is slower.
The tach does hang at 4k. Again, if the tach was accurate, then there would be a change in engine pitch at the 4k point. There is not. Further, the speedo would also stop accelerating when the RPM's stopped increasing (it does not).
Further, when driving the car, do you FEEL the acceleration hang at that point? Forget for a moment what the tach says because if the tach were accurate there is no way you would not feel the change in acceleration.
I agree with the mechanic. The problem is in the cluster. Note, the 1999-2004 cluster gets speed and RPM's as an electronic signal from the PCM. For proof, use your SCT and monitor/datalog RPM and speed.. Reproduce the problem. Graph the results. If the RPM curve is smooth, this PROVES it is in the cluster. If the RPM curve shows a hump at 4k, but the MPH is smooth, this means we have a mystery to solve.
As to why it does not happen in 1st gear, maybe because in 1st gear everything is climbing faster. Perhaps the momentum of the needle movement carries it past the "hang" point. In the other gears, the acceleration is slower.
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