lexus082

You have to remove the back seat to gain access to the fuel pump "service panel".

The amp is located in the trunk, right hand side.

Figured out it comes of igniter #1. So I got the tach speed off of that (basically inspecting the condition of the wires). After I found that tach signal to be correct and the one at the diagnostic port next to the engine, I swapped out guage clusters and found that the tachometer was displaying the wrong rpm's. At 700 rpms the tach was showing 250-500 rpms. Now I just have a misfire to resolve. :cries: Damn Misfire :chairshot:

I am trying to find out where the tach signal is created/generated? Does it come from the ignition coils?

Does anyone know where the tach. signal comes from. Does it come from the ignition coils?

I have a 94 sc400. It has the same engine as the LS. Here's my problem: I have a misfire that occurs I think just at idle. So basically to sum it up, I have replaced the plugs, caps, rotors, and the wires are only two years old. I pulled each wire (One by One) to make sure I didn't have a dead cylinder. So heres the symptoms: --The idle speed is within spec. approx. 700 rpms in park and 583 in gear. --Tachometer is not getting the proper tach. signal. --Have a random misfire. --Car shakes slightly after it warms up when the idle comes down to 700 rpms. --Engine mounts have never been replaced. Any thoughts after reading those symptoms? I have read that a misfire can be caused by a vacuum leak, leaky egr valve, weak fuel pump or fuel pressure regulator, dirty injectors, water in the gas...

Sounds like the sensor is bad.

I also have an improper tach signal. What does your tachometer read at idle and at cold start. My tach reads 750 at cold start idle and then drops to like 200-400 when its really around 700 rpms. Like the question was already asked does the tach signal come from the camshaft sensors? I looked in my parts book and there's nothing listed as a camshaft sensor. There's only crank position sensors listed.

It should put out a code 41 if the tps sensor is going bad. No precautions, but you should re-calibrate the tps sensor. Go to: www.lexls.com you'll find how to re-tune it there under the engine tutorial section I believe. Even if you don't have a code it may be starting to fail. Especially if its the original sensor from a 92 model.

You should stick to the Toyota Type IV. I would go ahead and do another drain and refill. And if your tranny fluid isn't red/pink and dark then I would continue to do drain and refills every oil change until it cleans up. Some members have had bad luck with tranny flushes.

Not sure where that came from. But that squeak may very well be from the drive belt tensioner. I had to replace mine when it started squeaking. I would go to www.partsamerica.com Here you go: http://www.partsamerica.com/ProductDetail....819&PTSet=A One of the few non oem parts I have used. Haven't had any problems with it since and that was about two years ago. Pretty good deal for that price.

Could be the tps sensor. I have a new Lexus tps sensor, part number (89452-22090) that I could let you have cheaper than what the dealer wants. You can e-mail me if you find you need a new one: OBRIE00@comcast.net Does your check engine light, or TRAC OFF, or TRAC light come on at all? Just asking in general.

lextech.org

Tonight I ohmed all the plug wires and they were all within spec. So I'll be pulling each plug wire one by one to make sure they're all working properly.

I had a toyota dealer check for a vacuum leak. They didn't find any. Checking the resistance on the two year old oem lexus plug wires. Maybe I'll get lucky.. I doubt it.