2006 4Runner 4.7L acceleration issue

I have the 4.7L V8 and I am having an issue when accelerating where it feels like I momentarily lifted my foot off of the pedal, and then resume accelerating again. Now this issue only happens at approx 2000, 2200, & 2400 rpm. Below 2000 rpm and above 2500 rpm, I NEVER have this issue. It is very consistent at those rpms too, it will happen 100% of the time that I reach those rpms. Even when on the interstate, if im hovering around any of those rpms and I try to very slowly accelerate, it will start to accelerate and then rpms decrease slightly and back and forth until I give it enough throttle to move on past that point.

So what have I tried already? Let me first start by stating that I performed a water pump and timing belt change around the time I started noticing it. I'm pretty confident that I was seeing this issue ever so slightly before I did this work, but I can't say that with 100% certainty. Since then, I have replaced the accelerator pedal. I cleaned the throttle body, but that didn't help. I purchased MAF cleaner and cleaned the MAF sensor. I then ordered a remanufactured throttle body from A1Cardone and that made no noticeable difference.

If I step on the accelarator over 50%, then there is never any hiccup, but of course the rpm is much higher than the range I have the issues in. I do a lot of interstate driving (approx 200 miles a day) and my cruising speed seems to be in the ballpark of 2000-2400 rpm, incidentally.

Any thoughts on where to go next? Thank you for any suggestions in advance.

 

Since your shotgunnin, why not try the fuel filter? At a lower rpm than the troubled 'targeted' rpm, fuel demand is lower, and above the 'targeted' rpm, is enough pressure to force the fuel through. Just a thought. With the high tech cars of today, mechanics & trouble shooting has a hard time keeping up with the speed of the mfg'd advances. That is why I drive older less advanced wheels. But someone has to be the guinea pig.

 

I suspect something is a tooth or so off in the timing related to the timing belt if it didn’t do it before.

 

If timing is a tooth or so off, wouldn't the problem exhibit itself through the entire rpm or speed range? I don't know, but with the on board computers managing nearly all the mechanical functions (as well as others) there is a limit as to what the on-board computers can overcome when it comes to overcoming mistakes in some types of DIY repairs. Also, why did you replace the accelerator paddle? Just curious since the fuel management, timing, acceleration, and stuff like that is managed by the computer, ox sensor, etc. These new cars are a nightmare to work on. But so is $125.00 (or more) per hour labor charge.

 

I replaced the pedal because the symptom feels like I just left off the gas momentarily. The RPMs drop as well. The pedal has a sensor that detects the position and sends that to the throttle body. I’m an electronics tech and can use a multimeter well. I tried testing it, but didn’t have much luck. There is no noticable problem when the car is in neutral and rev it thru that RPM range though. I can’t test it while driving the car, so I found a used one for $25. I figured it was worth a try, but the symptom didn’t change at all.

 

Well, all I can contribute at this point is this: A Porsche 919 E race car. One of the very best race cars of any vintage. It is now lapping faster than F1 cars.

 

Is the Throttle Position Sensor new?

 

That is part of the throttle body assy, I believe. I purchased a reman unit from A1Cardone. The sensor on the side of it is riveted on.

 

I have 2007 4runner doing the same issue .. but it won’t do it when on cruise control

 

I’m aware this post is from 2018 but I’m having this EXACT issue with mine.

I also noticed it after doing a complete timing belt job, but I also had issues when doing it, so I had to tear it down and do it again because it had jumped a tooth or two after the first test drive and the CEL came on from the result of one of the bolts on the tensioner was over tightened *rented torque wrench* and broke off.

I don’t have any lights on the dash but I’m gonna guess it HAS to be a timing issue since it coincidentally seemed to start around the time of doing the timing belt for us both..

 

Timing would be my first assumption. Check timing. The procedure I use is line up the cams with their marks, crank with its. Keep the belt tense on non tensioner side and slack on tensioner side. Pull pin and release tensioner to take away the slack. Double check everything lines up.

I had a similar issue on my SC430 (almost same engine) but it ended up being a weak mass airflow sensor. When I took it in for airbag recall the master tech, who drives his SC to work everyday said the MAF was acting weird around 3k on shop scope.

I got a new aftermarket one on eBay for sun $20, reset learned ecm values, and that fixed the problem.

 

Thanks for the response, I tore it down to check the timing and the timing looks to be fine. I did see some rubber wear on the tensioner pulley which isn’t normal that I’m aware of so I planned to go ahead and replace it before putting it all back together. I cleaned the MAF but will definitely give that a shot aswell.

 

Cleaning didn’t work for mine and it only had 32k on it. I bought the cheapest once I could find new on ebay and it fixed the problem, 17 bucks.


Here is one

https://www.ebay.com/itm/1337809311...62W-PCbTom&var=&widget_ver=artemis&media=COPY