Speedo Gear Problem?

Alright, I've been waiting for a while to get around to asking about this but I'll ask now.

This only happens when I'm going down the highway and it's happened about 25 times in the last 2k to 3k miles.

I'll be going say 65 to 70mph and I'll press down the accelerator but not enough to downshift. The jeep starts to accelerate slowly and then the speedometer reading shoots up to about 85mph then quickly back down to about 55 and then back up to the speed that I am going.

during this happening the check engine light comes on, and there is a jolt that seems like the drivetrain is quickly locking up then returning to normal with the check engine light going back off.

I did a PORC SYE on my jeep, had some leakage, re-did the seals about a week later and then this started happening. It never happened before I re-did the seals.

I checked the speedo gear and none of the teeth seemed to be ripped off or anything, it seemed just as it did before I did the SYE.

Also, when I re-did the seals I inspected the main output shaft to make sure nothing was wrong with it, and I found this little indention sort of thing near what seems to be a grease hole. This is located on the front end of the shaft.

Dead spot on your TPS possibly?

anodyne33 said:

Dead spot on your TPS possibly?

Click to expand...

yeah, see the only thing is that the TPS is in the engine bay is it not? And it only started happening after the second "install" of the SYE.

And I have noticed that it happens more often when the road is more rough, like where they have paved asphalt over concrete expansion joints and the asphalt buckles up.

its at the correct setting.

Pull the engine codes! I bet it says you've got a bad speedo sensor.

the check engine light only comes on when it happens though, it just goes back to normal right after. will it still throw codes?

Codes can be stored without the CEL being on.

Even though the light goes out, the code is still stored for quite a while. Up to 50-restarts I think. Assuming it's the 95 you're talking about, do a search for the key-on-off trick to get it to flash out the codes.

Alright, I'm going to hopefully run a scanner today and pull some codes, but I'm starting to think the problem really is my TPS. This is because if I'm sitting at a light or just kinda idling in park sometimes my jeep just cuts out and stalls....

Anyone know if this is it?

And, where is the TPS? How much does one cost? and how difficult is it to replace?

Thanks

The TPS is on the Throttle Body, hence Throttle Position Sensor. It is very easy to replace, and runs about $60 from the dealer.

Is that the new 32 spline output shaft? Mine didn't have a hole like that and those splines look a little twisted to me. It just doesn't look right. Speedo gear may not be the problem.

It looked as if the shaft was hollow. The hole looked as if it was supposed to be there, but didn't look like the splines should be that twisted.

I think the stalling and speedo jumping is just a TPS problem tho. Plus sometimes when I start it, it idles really rough, like the engine is vibing because it's in park...