kimchee

my 2000 4runner currently has 52000 miles on it and started surging about 10k miles ago.

its very noticeable when the engine is cold. if the engine hasnt warmed up FULLY it will surge if i give it a moderate amount of gas. mostly notice it at lower rpms but i can definitely still feel it all the way through the range.

when the cars warmed up to full temp it runs fine unless i really stomp on the gas. if i floor it i can feel it surging a bit and then seems to smooth out.


the cars been supercharged since 1k miles. never had any sort of problem except for the recent surging and accompanied feeling of a slight power loss.

since the surging started i have done the following to try and eliminate the problem.

1. replaced fuel filter
2. cleaned MAF sensor
3. had the dynamic belt tensioner installed.
4. replaced clutch
5. installed 7th injector kit
6. had injectors cleaned (asked dealer to do this when I had my last service. dont know if they did or not but i remember paying a big chunk of change. also have dumped in injector cleaner a few times just to make sure)

still surges.

Can anyone suggest what to check next?
any way to check the A/F sensor and o2 sensor without purchasing new ones?

would a not so clean throttle body cause surging?

could my fuel pump have worn down enough to starve the engine at open throttle?



since these problems didnt exist for 40k miles im pretty sure the SC was installed properly by my dealer. but is there anything in particular I should check for that might cause sudden surging? boost guage has always shown consistent readings while driving.

Thanks for your help guys!
I hope i can get this resolved. im starting to get worried

rimpainter.com

Correct me if I am wrong, but you should be under the 5yr/60K powertrain warranty. According the SC guys, the SC does not void your warranty in any way.

MTL_4runner

This is obviously engine management compensating for some problem.
Does it have a CEL? Any codes you can pull?

Quick stuff to check would be cracked or disconnected vacum lines.
Also check the throttle body to see that it isn't all gunked up with carbon (if so, clean it).

Best thing would be to get a tool to check the output on the O2 sensors to see if you are surging from a lean / rich problem or if the engine is playing with the idle. If you have a PDA then I suggest the one in my sig......helps a ton in diagnosis like that.

kimchee

ive takin it in and they said they couldnt duplicate the problem.
said everything felt fine.

idiots

kimchee

been thinking of getting an obd 2 tool but dont know much about them and dont have the cash right at the moment after dumping so much into the car.