Idling Troubles on a 91 GT

[brandonyaw]

I really need some help here. My fiancee drives a 91 Toyota Celica. Its a GT, but I can't remember the engine size. Here is whats happening:

The past few weeks, after turning the car on, it "bounces" in idle, as in, the engine is bouncing up and down about 5-600 rpms. Even when you push the peddle in, the rpms are bouncing, but just at a higher level. Even in gear, when traveling at a constant speed, the car starts jolting as if the rpms are going up and down. Usually, when putting a load on the engine (i.e. accelarating), the jolting stops, but when steady (constant speed, idle, etc) the boucing of the rpms resumes.

It gets worse, the rpms keep bouncing down lower and lower, until it bounces so low, the car dies. Even if your traveling, and you take it out of gear, the rpm's come down so fast it kills the engine.

So, this morning, her car won't even run but for just a few seconds. The idle is bouncing now about 1000 rpms, or more. If I try to give it gas, there is NO RESPONSE from the gas pedal, unless the pedal is all the way in. So the car either bounces at idle, or jumps up to 5000 rpms, then back down and quickly dies.

That is the best I can do at explaining it. The car won't even stay on for more than just a few seconds now. What do you think it could be?

[Pineapple]

First try cleaning the throttle body with throttle body cleaner. After you remove the rubber intake pipe, you can see inside the TB. At the bottom of the TB is a few holes. Spray lots of cleaner into them. Also remove small rubber hose on the TB ONE at a time and spray INTO the TB through the openning. Put the small hose back BEFORE you remove next one. Open the butterfly and clean it. Spray into the manifold while you're at it. You should have a bit cleaner left. Start the engine, open the throttle and spray into manifold until you got nothing left. You may need two can to clean everything. After cleaning, set idle and timing.
BTW the engine is 2.2L 5S-FE.

[brandonyaw]

I did exactly what you just described last weekend. Some people from the tacoma board mentioned the throttle positioning sensor (TPS). I'm going to search for similar posts and see what comes up. Ever messed with the TPS?

[19Celi87]

Usually surge is either intake leak, or fuel pressure problem. TPS is one of those things I personally have found, just is never the actual issue. Anyone who has tried to get one off the TB to inspect or replace will tell you they don't move after the factory sets em'. Especially after 10 plus years. Fuel pump, presure reg., and even the gas cap gasket drying up can affect pressure.
Does it for the most part drive and preform normally when in motion and in gear?