97 idle fluctuation

So.... I have been working on ressurecting a 97 tacoma with a 3RZ. It has 93k on the ticker. This truck was parked on the wrong side of town and suffered a bullet through the intake plenum and valve cover as well as the wire harness, which melted at the impact point. To this point I have replaced the harness, valve cover, intake and some relays. I can now get the truck to start and run but my main problem right now is the idle fluctuates high to low to high in a continuous cycle. temp does not effect the idle issue, It does it when its cool and warm. The little valve that pushes controls the throtle pushes it in and out. I have checked all the hoses and cleaned the TB but it doesnt help. The coolant is topped off, it has new oil and filter, cap and rotor. I also checked the TPs which seems to be working fine.
What do you think I should try troubleshooting next?
Any help is appreciated. Thanks

 

Someone shot your taco??? Wtf

 

I inherited it that way LOL, I do feel good about the progress though.

 

Poor taco try sea foaming it? Check for shit in the gas tank? MAF sensor

 

will try seafoam tonight.
Thanks

 

Anytime! I think there is a sticky on it

 

O2 sensors could be adjusting the lean/rich mix... Just a thought I would seafoam it first. Replace fuel filter as well

 

I could be missing something..but you said that it fluctuates between high and low idle..but that is normal.

Low idle is ~750 and high idle is ~1100.

Unless it does it in rapid succession.

Need more details.

 

The OP stated his idle fluctuates up and down while cool and warm. That is not normal. It should idle at about 1100 until warm then drop to 750ish.


I recently helped a friend get an old Ford running that had sat parked in a field for four years. We had to replace fuel tanks, pumps, filters, spark plugs, wires, dist, and cap. It was a nightmare but ran like a champ when we got it done.

 

Mine has always fluctuated between high and low idle when at operating temp. It runs fine...

 

I think he means in rapid succession. ive heard of that before.. its weird

 

Doesn't sound right. My cold idle range: 1000 to 1250. Operating idle: 600 to 850.

 

My Tacoma had jacked up fluctuations like this, not too rapid, but very noticeable.

Turned out to be a bad throttle position sensor

 

Yes in rapid succession, definitely not normal. Gonna run to the parts store and get some seafoam hopefully it stops raining here so I can work on it.
Thanks for all the replies guys
Cheers

 

Rain??? what's that??

 

My low idle is at about 650 rpm's

 

Alright, Seafoamed, and carb cleaner looking for vacuum leaks, no dice!!!. Still doing it. Grrrr.....
What should I try next?

 

Colorado weather, 84 one day and rain and 54 the next, gotta love it.

 

The O2 sensors may be adjusting your a/f ratio searching for correct most efficient burn.

 

Looks like I will try the O2 sensor next.
Thanks for the input. I may tow it to the autoparts store and get it scanned first, see what codes they pull.