Erratic idle and stalling at stops

Traakon

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Mar 22, 2015
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248
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Queen Creek, Az.
Desert Dino - Not sure where you got that it was not her daily as it actually is. We do have other vehicles but the Bronco and Jeep are long term projects and My Lincoln is not a daily kind of car. While CBT had the 'Cruiser she did use the Lincoln for short trips to the store but not as a regular go everywhere vehicle. Frankly it draws too much attention both good and bad.
 
Joined
Oct 12, 2013
Messages
58
Location
Folsom/Sacramento
I know this is an old thread, and I know there are a number of threads describing fzj80s with similar symptoms, and many don't have resolution. Since these threads were so helpful for the 2-banana mechanic such as myself, I wanted to add to how I resolved the problem with my 93 that had similar symptoms. It took my months to finally chase down the problem. The erratic idle, engine hesitation, bumbling acceleration was not persistent, so it made it harder to diagnose. Plus, OBD code 71 (egr issues) poppep up from time to time.

I checked the intake tube for cracks, checked emmisions vacuum lines, used chevron techron fuel injector cleaner, replaced the engine coolant temperature sensor, checked the condition of the harness near the egr, replaced the fusible link, replaced the O2 sensors, replaced the ecu, replaced the air flow meter, and pretty much followed leads from many other threads related with this problem.

What I discovered was by chance. I pulled the dipstick out while the engine was running, and the engine immediately went into a stumble similar to what was happening erratically when I drove the vehicle. When I reinserted the dipstick, the engine ran smooth again. Then, I removed the oil filler cap, and the engine went into a stumble again.

So, it dawned on me that there could be a vacuum leak through any of these areas. I bought a new gasket for the oil filler cap, since the old one was brittle and could be allowing air in. That didn't fix my problem though. What fixed my problem was tightening the valve cover bolts that were loose. There were 2 bolts at the rear of the engine that were so loose that I could almost remove them with my bare fingers. Once I reset the ecu, and after a few drives, the engine ran like a champ. The 71 code never came back (it has been 3 months now).

I would add that replacing the valve cover gasket may be necessary if tightening the bolts don't provide an improved seal.
 
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Traakon

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Mar 22, 2015
Messages
248
Location
Queen Creek, Az.
Nice addition to the thread. I'm going to go out and just verify all my bolts are sound even though I have not had a reoccurrence of the problem in some time.
I have given up on getting the EGR code resolved. After CBT contacted Toyota about it and the engineer said "That's not possible on a '93" I sort of resigned myself to a little amber engine on the dash.
 
Joined
Oct 3, 2018
Messages
20
Location
Dallas, TX
I've been searching and reading all week about a very similar idling issue I've been having, and after reading this thread I feel like I'm in for quite an uphill battle.

One thing I'm still not entirely clear on: can I completely remove the vacuum system from my truck? Like every single bit of it? ('94 OBD1 1FZ-FE)

The previous owner removed the EGR system and some of the vacuum system, but there's still random hoses and hard lines visible. Some are capped, some are not.

This is my first foray into a vacuum system so if possible I'd love to just remove it entirely and never have to worry about it again.
 
Joined
Nov 9, 2012
Messages
6,560
Location
Olathe, KS, USA
I've been searching and reading all week about a very similar idling issue I've been having, and after reading this thread I feel like I'm in for quite an uphill battle.

One thing I'm still not entirely clear on: can I completely remove the vacuum system from my truck? Like every single bit of it? ('94 OBD1 1FZ-FE)

The previous owner removed the EGR system and some of the vacuum system, but there's still random hoses and hard lines visible. Some are capped, some are not.

This is my first foray into a vacuum system so if possible I'd love to just remove it entirely and never have to worry about it again.
No, not ALL of it. There are areas that need vacuum from the engine. Brake booster is one of them.

Work on diagnosing the actual problem, not just symptoms.

Have you started your own thread on what the issue is? If not, maybe start there with the key facts, the symptoms, and what you've done to date.
 
Joined
Oct 3, 2018
Messages
20
Location
Dallas, TX
No, not ALL of it. There are areas that need vacuum from the engine. Brake booster is one of them.

Work on diagnosing the actual problem, not just symptoms.

Have you started your own thread on what the issue is? If not, maybe start there with the key facts, the symptoms, and what you've done to date.
I was contemplating starting my own thread but didn't want to get crapped on for not doing enough research/searching. I'm new to vacuum systems (& Land Cruisers) so I have a bit of learning to do.

I also don't yet have the tools necessary to troubleshoot much of the suggested items mentioned in this thread and others.


Funny you should mention brake booster though. The past few weeks my red "BRAKE" light would pop on and off, usually only on cold mornings, but recently it been occurring more on every drive. I decided to clean all the dirt/mud off my brake fluid reservoir and noticed it was at the minimum line. So at lunch today I topped that off.
Miraculously that cured MOST of the violent engine surges I was experiencing. The truck still won't ever hold an idle and I'm still having to drive with both feet, but boy is it so much smoother.

I still don't understand why the hell they designed an engine that can be so unbelievably crippled by something as silly as low brake fluid. As a mechanical engineer by trade, it just boggles my mind.
 
Joined
Aug 22, 2018
Messages
57
Location
WI
It seems that there's an equal amount of owners solving this issue with wiring harness, valve cover gasket, sensors, egr issues, and who knows what else.

Sometimes it's not feasible to replace all the things.

My plan is to start with the wiring harness around the egr. Cut out a good length of all the wires touching the EGR hose. Although none look melted, I know enough heat can do it. Then crimp in longer new sections to tie up and out of the way.

It only makes sense to replace questionable parts of the harness before any of the sensors. Also need to check it near the glove box.

Does anybody know what gauge wire it is?
 
Joined
Oct 21, 2007
Messages
1,568
Location
Columbia, MO
I do not but will be following along!

It seems that there's an equal amount of owners solving this issue with wiring harness, valve cover gasket, sensors, egr issues, and who knows what else.

Sometimes it's not feasible to replace all the things.

My plan is to start with the wiring harness around the egr. Cut out a good length of all the wires touching the EGR hose. Although none look melted, I know enough heat can do it. Then crimp in longer new sections to tie up and out of the way.

It only makes sense to replace questionable parts of the harness before any of the sensors. Also need to check it near the glove box.

Does anybody know what gauge wire it is?
 
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