Rough idle then shuts off

Tiny
TODDAKINS
  • MEMBER
  • 1990 TOYOTA PICKUP
  • 3.0L
  • V6
  • 2WD
  • AUTOMATIC
  • 200,000 MILES
Took a trailer load to the dump, no issues, on the way home it got a little warm [1/4-1/2 from cold]. All was fine until I got back home and stopped, that's when the engine stopped. I started it back up with not problems how ever now the motor will only stay running if I give a little press on the accelerator or turn on my A/C. Acceleration is 100%, no noises no smoke no loss of any power. To try and correct this rough idle then die I have replaced.
fuel filter, timing belt and all pulleys, water pump, plugs, wires, cap, rotor, used a can of break clean over the entire top of the engine to listen for a vacuum leak with A/C on and the RPM did not change. OBD1 - code - "TPS inoperative". Replaced with new TPS and now have 0 codes yet the idle is rough until it shuts off just as before. I cleared the codes by removing the "15 inj" fuse for 30 seconds and replaced it then took it out to the interstate 99 North. 2% traffic so I opened it up. I drove to Merced, 60 minutes at 70-85 mph then back. Not one time did it go more then 1/4' past the cold line! Got back home to the same as when I left. Does anybody have any ideas? The Toyota dealer is closed because of the Corona virus so for two weeks I have been hit and miss.
Wednesday, April 29th, 2020 AT 9:46 PM

3 Replies

Tiny
TOUGHDIVER
  • MECHANIC
  • 224 POSTS
Hi,

Your curb idle speed may need adjusted make sure your throttle valve and intake bore is free of carbon. I'm giving you schematics and instructions be to follow below let us know if you more information

https://www.2carpros.com/articles/stall-at-idle

Thanks
Joe T.
1. When setting the idle speed make sure that
a. Air cleaner is installed.
b. All vacuum hoses are connected.
c. Make sure that all fuel injection wiring connectors are fully plugged in.
d. Engine should be at normal operating temperature.
e. All accessories should be turned off and the transmission in neutral.
2. Connect a tachometer to the engine.
Tachometer Hookup
Note: Never allow the tachometer terminal to contact a ground as this could cause damage to the ignition system. Some tachometers are not compatible with this ignition system, so please confirm the compatibility of your tachometer before connecting it to vehicle.
3. Run engine at 2,500 rpm for about 2 minutes.
4. Set the idle speed by turning the idle speed adjustment screw.
Idle Speed Adjusting Screw
Idle Speed: 800 rpm
5. Remove tachometer.
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Thursday, April 30th, 2020 AT 12:03 PM
Tiny
TODDAKINS
  • MEMBER
  • 2 POSTS
I pulled the upper intake manifold off and replace the gasket. Still no change in the rough idle and die yes. However if I have the air conditioner on it will idle but it doesn't want to and lets me know. Any other suggestions? Every little bit helps.
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Sunday, May 3rd, 2020 AT 12:13 PM
Tiny
KEN L
  • MASTER CERTIFIED MECHANIC
  • 47,663 POSTS
If we can see the engine run it can help us. Can you please shoot a quick video with your phone so we can see what's going on? that would be great. You can upload it here with your response. Is the check engine light on if so lets get the codes this guide will help:

https://www.2carpros.com/articles/toyota-trouble-code-definitions-and-code-gathering-method-1990-1995

Please run down this guide and report back.
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Thursday, May 7th, 2020 AT 10:53 AM

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