Smooth idle but surging/thrusting on acceleration

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symlink

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So I just bought my 99 4runner limited with the 3.4 from a used car dealer. I noticed it surging the other day while throttling down it goes away as far as i can tell when you let off the accel to just light pressure when you reach ur speed. But its like its choking for gas sometimes or having troubles breathing. So far I've changed the plugs and plug wires dealer had the wrong plugs in go figure.. i went with the copper core ngks and good wires. Also replaced air filter and replaced the fuel filter and cleaned out the maf sensor and throttlebody to no avail. The maf senser i couldnt get out so i put a rag in the air box and sprayed it down with maf cleaner and let it dry. Other than im not sure where else to look possibly cat or actual fuel pressure? Possibly compression test? Also there is no check engine light


Thanks guys I appreciate and help you can give just starting to learn the 3.4 after my 87 with the 22re I hope i can get this sorted out.
 
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Getting a CEL? Maybe your Throttle position sensor is on it's way out. Why couldn't you get your maf out? Screws stripped? You should get that out and clean it properly.
 
Yeah, the screws are stripped out... the next thing I know to do is to just try and drill the screws out with a small drill bit. But no check engine light at all right now, and the check engine light does work it illuminates when you turn to accessory position. Thanks any ideas on getting the screws out? I guess I will check into the TPS next
 
symlink said:
i went with the copper core ngks and good wires.
Click to expand...

Should have went with Double Ground Platinums. Are these copper cores at least Double Ground? They pretty much have to be.

And define "Good Wires".

Our 4Runners are very fussy and basically the only way to ensure optimum and efficient performance is to stick with Genuine OEM Toyota parts
 
SpidermanGeek said:
Should have went with Double Ground Platinums. Are these copper cores at least Double Ground? They pretty much have to be.

And define "Good Wires".

Our 4Runners are very fussy and basically the only way to ensure optimum and efficient performance is to stick with Genuine OEM Toyota parts
Click to expand...

Yeah they are double ground NGK's, the dealer had single ground champions in there. Ill check what wires I've got. Also it was doing it prior to me changing wires/plugs as well. I purchased the import direct spark plug wires from O'reillys.. I should have probably purchased denso wires.
 
symlink said:
Yeah, the screws are stripped out... the next thing I know to do is to just try and drill the screws out with a small drill bit. But no check engine light at all right now, and the check engine light does work it illuminates when you turn to accessory position. Thanks any ideas on getting the screws out? I guess I will check into the TPS next
Click to expand...

If they are really stripped you'll have to drill them out. I suggest left hand drills which may back them out on their own. If not, then use an extractor. Use Allen head screws as replacements. Get the maf cleaned first before you tear into the TPS.
 
Alright can do!.. Thanks also I should mention that there is only 135k miles on the motor but I have no prior knowledge of what the previous owner has done etc. so trying to get everything on a level that I know whats been done and what has not.
 
Well I finally got a CEL today on the way to work. Hopefully I will finally be able to isolate the issue at hand once I'm able to go get it scanned during my lunch break today. I'm personally thinking I need a new CAT as it seems like the engine is struggling for air. But who knows, I also went ahead and replaced the TPS as when I checked for resistance it didn't seem up to spec. Ill keep you guys posted thanks for the help I appreciate it.
 
So got the code read and its a p1133 code.. i suspect the o2 sensor being bad but not completely sure could it be the maf? Also before the cel came on i ran a scan with a friends scanner and everything checked out except there was a big red X next to the cat could a bad cat cause that code? Id imagine so im going to do some searches and see if i can come up with anything.
 
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im not 100% but I would deff still clean the maf n try it as that the code I got when my maf was dirty. but I didn't surge and old alittle sputter on take off. but wouldn't rule out it being a 02. but let start with a cheap( free if you can drill out the screws) fix n go from there.
 
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The CEL went away before I tore into the airbox to remove the MAF, I did manage to get the MAF out but I had to drill it out and in the process messed up the airbox. So i had to find another replacement cleaned the MAF exceptionally well and reinstalled. Also replaced the PCV as it was right there in my face. Seafoamed the TB aswell and drove it around. The hesitation on accel is still there but not nearly as bad as before. Not sure what else to do besides digging into the engine and doing fuel test etc. and maybe replacing that AF sensor since my 4runner is the cali-emission compliant one -.-. May be possible my cats are plugged? or restricting air flow. I have a diagnostic cable on the way. Any other ideas?
 
Since you have 135K on the truck and no past history I would bet the a/f sensor is original. I would change that next, I bet that's the last link in this issue.
 
You may need to replace the MAF regardless of how clean you got it. My MAF had been spotless but on cold mornings this past year it would surge until the engine got to at least 120F. With a live data scanner I was able to see the MAF when surging wouldn't read anything (no output). $100 later with a genuine OEM MAF all is good to go, plus my MPGs have gotten better.

Those MAF screws are JIS screws, and need JIS screwdrivers to properly take them out. Kball's suggestion to use allen head screws is spot on.
http://www.amazon.com/Hozan-JIS-4-JIS-Screwdriver-3rd/dp/B00A7WAHTU
 
Yeah, I had to go with a cold air intake to make due until i can find a replacement airbox. It threw a check engine light this afternoon and ill get it scanned in the morning to see what codes its throwing. I wouldnt be surprised if its throwing all kinds of crap now. I also can bet thats its the original a/f sensor aswell. Ive also got to call around to find a airbox that matches exactly what I have. I love me some clemson tigers. Ill keep you guys posted on my findings. I appreciate all the info and guidance.
 
Well update.. still have not fixed the issue. However the code p1133 is persistent so i purchased a new a/f sensor denso brand.. i also got the techstream cable working today so id figure id share some screenshots that way you might be able to see whats going on. Also i have not had time yet to put in the sensor.
34hsyvp.jpg
 
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Changed the A/F sensor with an OEM denso one, this morning all seemed well and seemed like it had fixed the acceleration issue. However the CEL came on this morning on the way to work. I did not clear the codes when I put the sensor in, so ill scan it and see what it pulls later this afternoon. If its p1133 should I just clear the code?
 
You can clear it but since it just came back on it will probably come back on again. Once the new sensor is in the CEL should not have been tripped unless it saw a fault again.
 
I'm guessing now that your pre cat O2 is new and working good the computer is not seeing what it wants at the post cat sensor. Probably because it's worn out also.
 
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