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Discussion Starter #1
The throttle on my '97 TBird 4.6 seems to kind of stick at around 1200rpm or higher sometimes, making it harder to stop the car at a light.
I changed the IAC unit a while back due to a varying idle and it was fine for some time.
I have lubricated the throttle body's linkage to no avail.
Any suggestions? Thanks!
 

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ive had this same problem multiple time cuz my car seems to hate its TPS sensor..when it goes bad it idles high and it makes it hard to stop and the second i release the brake it lurches forward as if i was on the gas...DUDE..ITS UR TPS..throttle position sensor, and when u install it make shur you have the angle correct which is very simple or ur rpms will still be off..GOOD LUCK
 

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ive had this same problem multiple time cuz my car seems to hate its TPS sensor..when it goes bad it idles high and it makes it hard to stop and the second i release the brake it lurches forward as if i was on the gas...DUDE..ITS UR TPS..throttle position sensor, and when u install it make shur you have the angle correct which is very simple or ur rpms will still be off..GOOD LUCK
+1 Good luck getting those two screws off holding TPS on. Unless it's been changed prior, they're a bear to get out without breaking something. Probably have an easier job grinding the heads off where you can remove the TPS, then clamp a pair of vice-grips on the screws.
 

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Discussion Starter #5
Guys, hey Thanks for the replies!! I have replaced the TPS before about 5years ago...the screws came right out then with no problem, do these things go bad that often?-car just now has 97k original miles-we've had it since it had only 29k...may be I'll try anouther brand......are there any better than others? I was thinking may be NAPA??
 

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Guys, hey Thanks for the replies!! I have replaced the TPS before about 5years ago...the screws came right out then with no problem, do these things go bad that often?-car just now has 97k original miles-we've had it since it had only 29k...may be I'll try anouther brand......are there any better than others? I was thinking may be NAPA??
Make sure the voltage it's putting out is about .98v at idle. When it's racing, probe the wires, one end is 5v reference, I believe the center wire is the one that should read about .98v (I'm not positive). You can also slowly open the throttle (withOUT the engine running) and watch the voltage increase - it should do so smoothly with no spikes until WOT (which is somewhere around 4.6v I think).
 

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Good info on the testing procedure (watching the voltage as you open the throttle), but it's not a good idea to say that the TPS voltage should be 0.98V or any specific voltage at idle, the reason being that someone might come on here, read that, go test their's, and with a high likelihood find out their sensor isn't putting that out, which may lead them to think they have a bad sensor when in fact it isn't. There isn't a specification anywhere for a particular voltage that the TPS should be at. The specification for the TPS at closed throttle (which is considered 0-15° of throttle shaft rotation from the factory stop setting) is between 0.65-1.25V. These aren't adjustable like the older ones and they really aren't meant to be. The PCM has a very sophisticated ratcheting algorithm that accounts for the wide range of sensor output characteristics that will exist so that the relative throttle position of a correctly functioning sensor is always known. You could take two brand new sensors and put them on. One might read 0.7V at closed throttle and 4.7V at WOT, the other 0.92V and 4.8V, but both will function just the same. WOT voltage should be above 4.5V.
 

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well, with my experiance my cougar like to blow its TPS sensor...idk if it from me hammering on it all the time or if my upgrades throw out some odd codes and end up frying the TPS...what ever it is idk but when my idle spikes and i have trouble stopping, its time to go back to the junkyard for another TPS...goodluck my man
 

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Discussion Starter #10
Guys, I bought an Echlin brand TPS at NAPA and it says its made in the USA if that helps....it was about $7 more than the one I bought at Advance auto parts about 5 years ago.
It fixed my high/surging idle problem so all is good now-much easier driving now.
Thanks to all that responded!! Have a SAFE day on the roads!!-Rick
 

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Good info on the testing procedure (watching the voltage as you open the throttle), but it's not a good idea to say that the TPS voltage should be 0.98V or any specific voltage at idle, the reason being that someone might come on here, read that, go test their's, and with a high likelihood find out their sensor isn't putting that out, which may lead them to think they have a bad sensor when in fact it isn't. There isn't a specification anywhere for a particular voltage that the TPS should be at. The specification for the TPS at closed throttle (which is considered 0-15° of throttle shaft rotation from the factory stop setting) is between 0.65-1.25V. These aren't adjustable like the older ones and they really aren't meant to be. The PCM has a very sophisticated ratcheting algorithm that accounts for the wide range of sensor output characteristics that will exist so that the relative throttle position of a correctly functioning sensor is always known. You could take two brand new sensors and put them on. One might read 0.7V at closed throttle and 4.7V at WOT, the other 0.92V and 4.8V, but both will function just the same. WOT voltage should be above 4.5V.
That's what all the manuals say, but I will tell you, when my TPS was 1.05v at closed throttle, the car never idled or ran quite right at light throttle. I reamed out the holes in the TPS where I could adjust it - it's now at 0.98 at closed throttle and it runs SO MUCH BETTER (it's a brand new TPS, btw). It is what it is, I figured.
 
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