A car automotive acceleration(94 Camry)

[ganou]

A car automotive acceleration(94 Camry)
The key in the ignition switch and transaxle on P, turned on, then the

speed needle goes up to 3000r/m. The transaxle is changed to D, the car

can automatically run, and is faster and faster, without using

acceleration pedal. I have to use brake pedal to regulate the speed. When

car is hardly brake, it is shaking. About fifteen minutes a special

smell comes from engine, so I do not dare to drive it and pull it over.
Before this symptom, there are two problems:
1. The engine light is on. The code is 71.
2. The hose before the throttle body is broke.
Please give me some suggestion. It is horrible for it can automatically

run.Thanks.

[somick]

As far as I know a hose brings warm antifreeze into throttle boddy and keeps it from freezing. So the first step would be to fix the hose.

The next step I would open the throttle body and see if something is stuck there.

And of course you need to find what code 71 means.


Good luck,

Sam

[RIP]

Code 71 is EGR gas temperature signal low.

Possible causes:
EGR valve/hoses
EGR gas temp sensor or circuit
Vacuum switching valve
ECM

Troubleshoot the EGR, check the throttle plate and cable, clean or replace the idle air control valve, replace the broken duct. Sounds like the "broken hose" you're talking about is the 3 inch diameter upper air intake duct. It connects to the end of the throttle body. I've seen non California emissions upper ducts for $50 on the internet, California for $90.

As somick eludes to, the engine is getting too much air at idle possibly through an open throttle plate. The plate is visible in the throttle body when you remove that big 3 inch diameter duct. The plate should be completely closed until you open it with the gas pedal. Clean it with throttlebody cleaner and a toothbrush. If it appears ok then looked towards the idle air control valve. It regulates the amount of air at idle.

You gave me the impression the check engine light was on well before this idle problem appeared. Is that correct? If so, fix the EGR last.