Hello. My 1988 Camaro with a 305 and automatic transmission was giving me a code for a bad Throttle Position Sensor. I replaced the sensor, set the idle to .62 I believe, and the car shifts a lot smoother now. However, a new problem has risen.

I don't normally go full throttle from stop because I like my car, but while I was testing the new TPS, I decided to do it. The car just crawled, there was no slipping noise, no engine noise, it just moves very slowly. I let off the throttle, and the transmission catches and the car roars back to life. This would be a problem with the TPS, correct? Also, the car will be cranky if I want it to shift down on a steep uphill, but is fine other than that. Thanks for any help!

 

Other than locking up the torque converter clutch , there is not a single bit of electrics/electronics involved in the shifting of your transmission whatsoever . ALL shifting of gears is 100% mechanically controlled , so the answer is no to your TPS question .

 

Okay! I’m super new to working on cars, so please excuse any dumb questions lol. If it’s not that, could it be a kickdown cable? Would that have anything to do with it, because it only has problems when it’s on a super steep hill or when I slam on the gas, otherwise the car shifts perfectly smooth(if it was inside the transmission, it would do it on all shifts, right?)

 

Hi , no problem on the questions , no one was born with the mechanical specs of our beloved Camaros & Firebirds pre loaded into their brains so we all have to learn about them as we go through life with them .

Now , your "kickdown cable" is actually very much more than just a kickdown like in the days of old (a passing gear prompt when the go pedal gets stomped on) , it's actually a "throttle position cable" that the transmission uses to control shifts and to regulate the transmission fluid "line" pressure sent to the clutches that are themselves rather sensitive to having the correct pressure . I know it sounds crazy , but a misadjustment of that cable can very easily damage the transmission by causing the clutches to slip too much and burn them . There is a special set procedure for that cable that you should be able to find with a search here of "throttle position cable adjustment" .

 

Of course , since it hasn't yet been mentioned , the fluid IS filled to the proper level and is nice & red , and not brown , yes ?

 

Yup, red and full.

 

Is this the guide?

https://www.thirdgen.org/detent/

 

Absolutely , that's the one I was talking about . That right there is the only external to the transmission setting that can affect it's shifting ...

 

All right, sorry for the delay, today was the first day I had time to work on my car in a while, and I think the problem lays with the TPS.

I checked the TV cable and it seemed fine, so I checked the voltage on the TPS sensor while my dad pushed on the gas. The sensor reads fine unless I slam on the gas, where it reads Open Loop for like a second and then reads normal. Guess that's what I get for not buying ACDelco? lol

 

The problem IS NOT the TPS. It is internal to the transmission in some way.

The TPS has ABSOLUTELY NOTHING WHATSOEVER to do with transmission behavior, except for converter clutch lockup. The 700-R4 is NOT electronically controlled; as Orange said its controls are STRICTLY MECHANICAL, except for the TCC.

Note that I am NOT saying "your TPS is fine"; "don't change your TPS"; "don't buy anything but Delco"; NOT NOT NOT NOT NOT NOT NOT NOT. Only, that the TPS CANNOT cause the problem you are reporting. It might be causing OTHER problems, or might not; but it is CERTAINLY NOT causing THAT ONE.