View Single Post
Old 09-09-2021, 11:17 PM
MTX018 MTX018 is offline
Junior Member
 
Join Date: Mar 2020
Location: USA
Posts: 2
MTX018 is on a distinguished road
MTX018 MTX018 is offline
Junior Member
 
Join Date: Mar 2020
Location: USA
Posts: 2
MTX018 is on a distinguished road
Had a similar issue on my ‘93 4Runner with a 3.0 V6. My symptoms were more like an engine stumble. When the RPMs were dropping, the engine would shudder slightly and when it recovered, the RPMs went back up. If you RPMs are “searching” the engine won’t stumble but the RPMs will constantly fluctuate up and down. Searching is usually a result of a vacuum leak. Stumbling is usually a result of low RPMs or misfires (plugs or injectors).

Here is how I resolved my issues.

1 - Replace all spark plugs. This resolved 85% of my symptoms and was a quick, cheap fix. Some plugs were obviously fouled.

2 - Inspect all engine vacuum lines for cracks or tears. I ended up replacing them all 1 by 1. Again, a very cheap fix and easy. Will take you 30min. This will cure the majority of your vacuum leaks if the lines are older.

3 - Inspect the cold air intake (rear of air box to throttle body). It’s that big black pipe on the driver’s side of the engine. Replace if it is cracked. They are not cheap (~$30 or so).

4 - Drive vehicle again and see if symptoms are improved. If symptoms didn’t improve, continue.

5 - Remove throttle body, clean, and reinstall with NEW throttle body gasket. The throttle body gasket can leak also, throwing things off.

6 - Add a can of fuel injection system cleaner with your next tank of gas.

7 - Drive again and see if symptoms improve. If not, continue on.

8 - Raise your idle RPM up to 800-850. Sometimes, if your idle is too low, the 3VZEs can stumble a bit and try to die. Set when the engine is warm.

9 - Drive again and see if symptoms improve. If not, continue on.

10 - consider replacing your upper plenum gasket. This will also give you a chance to look at the fuel injector rails and connectors. Make sure they are not leaking and the connectors have a positive connection with the injectors. Clean the upper plenum before reinstalling. You do not have to remove the throttle body from the upper plenum.

11 - Drive again and see if symptoms improve. If not, continue on.

12 - Watch a video on YouTube by Practical Enthusiast “high idle speed easy fix”. He shows how to clean the idle air control valve on the back of the throttle body.

13 - consider removing all fuel injectors and sending them in for cleaning and a new o-rings


My guess is you will be back in action by Step 5 or 6 at the worst. Good luck.
MTX018 is offline   Reply With QuoteReply With Quote
 
Powered by vBadvanced CMPS v3.2.2

All times are GMT -4. The time now is 08:34 AM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
Search Engine Optimisation provided by DragonByte SEO (Pro) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.
User Alert System provided by Advanced User Tagging (Lite) - vBulletin Mods & Addons Copyright © 2024 DragonByte Technologies Ltd.
***This site is an unofficial Toyota site, and is not officially endorsed, supported, authorized by or affiliated with Toyota. All company, product, or service names references in this web site are used for identification purposes only and may be trademarks of their respective owners. The Toyota name, marks, designs and logos, as well as Toyota model names, are registered trademarks of Toyota Motor Corporation***Ad Management plugin by RedTyger
 
Copyright © 2020