97 3.4 low idle issue looking for help

[Serge627]

97 3.4 issue while in low idle, looking for help

Hey guys,

Just a bit of background. I recently picked up a 97 SR5 5spd w/ 203k on the clock. Initial inspection showed that it appears to have sat for a little while prior to me getting it. I got it from a guy who picked it up for his wife, from a lady from his church, ended up selling it without doing anything to it since his wife decided against the stick shift. Anyhow, engine appeared very clean, no rust and a manual trans for 2k had me sold.

It had a bad exhaust leak prior to the cat, which I fixed with a full new system.
I drained and filled the coolant, with Toyota red mix. Cleaned the MAF and TB and replaced the fuel filter. Oil looks good.

ISSUE:

Truck fires up immediately without hesitation, high idles to 2k rpm for about 10 sec. and then idles down to 600~ rpms. Will drive smoothly and without issue at all. Problem is as it warms up and settles into the idle rpm range it will begin to make a "surging" or rhythmic fluctuation in the idle sound, however this does not show on the rpm gauge, so it is not that drastic apparently. Almost sounds like it has a cam, but not in a good way lol.
When I first started messing with it, it did throw a P0300 and several P030x codes, indicating random misfire and specific cylinder misfires, however after testing/driving it for about 15 mins yesterday and seeing the same symptoms, there were no codes.

I have searched this site and other extensively and am aware of injector issues etc, however this does not seem the same, mainly based on the fact that it does accelerate and drive fine, its purely a low idle issue.

Any tips or help are appreciated.

 

[SpidermanGeek]

Did you remove the TB to clean it?

If the answer is no, it sounds like a gunked up IAC to me. If you're not carefull, TB cleaner or gunk from the TB will flood the IAC and possibly dislodge other crap that's in there, thus affecting the IAC's overall function. The result of that is typically weird idling/throttle issues.

If you did remove the TB, maybe you missed reconnecting a vacuum hose.


That's about all I've got. I'm sure someone more knowledgeable than me can do more for you.

 

[19963.4lsr5]

How oil is the gas in the tank if it sat 2 years or so?


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[baja1]

try this, you don't even have to remove the IAC. remove the IAC coil (there's a bit of soft sealant hiding the heads you can pick out) revealing the magnet (this is the armature) that is now a knob that will adjust your idle speed. plug the coil in and lay it out of way so you won't get a CEL. if you want to leave it like this dab a little epoxy on the armature to base to hold it in place.
I had already ordered a new IAC when I did this so I replaced it...but...it sure seemed like it actually ran better with the idle set this way. maybe my imagination?

 

[Serge627]

How oil is the gas in the tank if it sat 2 years or so?


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Not sure. Not sure how long it sat for sure either.
It had just under 1/4 tank when I got it, so I replaced the fuel filter and put 5 gallons of mid grade in it. Fuel that was coming from the fuel filter and lines did not smell like varnish, it smelled normal.

 

[Serge627]

Did you remove the TB to clean it?

If the answer is no, it sounds like a gunked up IAC to me. If you're not carefull, TB cleaner or gunk from the TB will flood the IAC and possibly dislodge other crap that's in there, thus affecting the IAC's overall function. The result of that is typically weird idling/throttle issues.

If you did remove the TB, maybe you missed reconnecting a vacuum hose.


That's about all I've got. I'm sure someone more knowledgeable than me can do more for you.

I did not remove the TB to clean it, I cleaned it in place. However the idle issue as described was present prior to cleaning the TB and MAF.

 

[19963.4lsr5]

It's worth putting some dry gas in the tank and a bottle of real injector cleaner.


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[amalik]

BG44K is the only injector cleaner I would run.

 

[19963.4lsr5]

I like Techtron and the Amszoil stuff. BG is good too but only place I can get it is Internet or through the local dealer.


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[Serge627]

All good points, I will pick some up and try that.

So far is the consensus that it could be a gas related issue? or is there other stuff that you guys would look at?

I was not thinking injector or ignition related issue (wires/plugs) based on the truck running well beyond low idle rpms

 

[Serge627]

UPDATE::

Ok fellas, heres a bit of new info from today.

Check engine light popped on, codes as follows

P0300, P0301, P0303, P0305

So multiple misfires, and then misfires on 1,3,5 All of which are on the passenger side of the motor????? ODD
Could this be a timing issue? Maybe that bank was not aligned properly when the T-Belt was put on and the pulley is off a tooth or two??

Again, driving the truck around the neighborhood it runs fine, accelerates fine, no stumbling, just normal driving and no hesitations. Its not until its stopped and at a low idle 650 or so, then it starts with the loping sounding idle, almost like a cam. Help

Also, used some carb cleaner to spray around for vacuum leaks, no change.

 

[19963.4lsr5]

You could pull the timing cover off and line up the dots and see what it looks like. The injectors on that side could be crapped up to.


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[Hoffie]

You probably have water in the fuel from sitting so long with a near empty fuel tank. A can of good fuel injection cleaner (BG or SeaFoam) should clear up the idle issue. Check all the spark plugs and/or just replace them. Was the air filter a stock filter or an aftermarket oiled air filter? The oiled ones tend to gunk up the MAF with an oily film.

 

[Serge627]

You could pull the timing cover off and line up the dots and see what it looks like. The injectors on that side could be crapped up to.


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This is what I was thinking. It makes sense that a misfire on the whole bank could be caused by improper alignment with the timing belt, right??

 

[19963.4lsr5]

This is what I was thinking. It makes sense that a misfire on the whole bank could be caused by improper alignment with the timing belt, right??

It is not much to check. I forget which cam the cam sensor is on.


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[Serge627]

Ok guys. I think I may have found the issue. Tell me what you think

Lined up at 0

Left bank

Right bank. Without cover totally off this was the best I could get, you can see its not aligned

 

[johnbyebye]

So, how exactly did this happen? Is the belt tensioner shot causing it to jump teeth? Or was the belt not put on right to being with?

Interested to know.

 

[Serge627]

So, how exactly did this happen? Is the belt tensioner shot causing it to jump teeth? Or was the belt not put on right to being with?

Interested to know.

I would love to know as well. I bought the truck w the rough idle and traced it down to in all likelihood being this as the culprit. Currently has a goodyear t/b on it, so the last replacement was not done at a dealership. Im guessing it wasnt put on properly. There are no signs of damage or excessive wear.

 

[johnbyebye]

I would love to know as well. I bought the truck w the rough idle and traced it down to in all likelihood being this as the culprit. Currently has a goodyear t/b on it, so the last replacement was not done at a dealership. Im guessing it wasnt put on properly. There are no signs of damage or excessive wear.

It's a good thing that this engine is non-interference. Being out of time in an interference engine can be really bad news.

 

[Serge627]

Well guys did the timing belt job today. New water pump, thermostat, tensioner and idler too. Anyhow, lines everything up to tdc, buttoned her up and BAM! That fixed it. Idle is fixed, no more cel, all is good!!!