Ever sense I got my 4runner it has had a miss. I have done a complete tune up (wires, cap, rotor, plugs). I have replaced the Mass Air Flow Meter. I have replaced the fuel pressure regulator. I have tested the TPS and seems to be ok. The thing that is bothering me is sometimes if I pull up to a light or make a quick stop (usually when it happens, but not all the time) the rmps will drop and it will act like it might die, it never does, but it wants to. Give it a little gas and it is fine. What am I missing?
Just a quick question for someone wiser than me.
- Thread starter Ekimrm
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Bad_Vision
Moderator
sounds like a tiny vacuum leak to me try replacing all your little hoses.
easy way to tell is to pump the brakes wile its running if the engine dies out or sounds like it wants to die then you have a leak
easy way to tell is to pump the brakes wile its running if the engine dies out or sounds like it wants to die then you have a leak
Last edited:
combatmedic
Banned
Fuel injector maybe?
Bad_Vision
Moderator
i would lean away from a fuel issue just becasue if it was a fuel issue it wouldnt make sense to have a issue at idle. at idle the injector pulse if standard at 400cc intermittent controlled by the computer the only way that would cause a engine studder is if you had a faulty injector nozzle in that case the thing would have issues threw out the power band.
this is how you test injector flow youl need 4 or 6 20 0z bottles depending on how many injectors you have.
1 remove the fuel rail with injectors attached to it
2 place one bottle on each injector
3 turn the key on
4 now you will need a set time like 30 seconds
5 turn the key as if starting the engine for 30 seconds it wont fire up because it has no fuel
6 once your 30 seconds is up take each bottle and measure the amount of fuel in each make sure you label which injector the bottle came from.
7 the injectors should have pumped the same amount of fluid within 2ml of each-other
if you have a injector that is way less or way more then the others it is not pulsing right and you should clean it out then retest if it does it again after cleaning you ether have a bad ecu control signal or a bad injector typically its a bad injector. ***note you can watch the injectors spray in the bottle if its not a fine mist that may also point to a bad injector***
8 after this test is done just replace the injector o rings they are cheap and it always helps to have a proper seal
if you have a small vacuum leak at idle you would loose pressure but as soon as you hit the gas your pressure would spike and be ok again. i still think its a vacuum leak almost 80% sure that's whats causing your issue
this is how you test injector flow youl need 4 or 6 20 0z bottles depending on how many injectors you have.
1 remove the fuel rail with injectors attached to it
2 place one bottle on each injector
3 turn the key on
4 now you will need a set time like 30 seconds
5 turn the key as if starting the engine for 30 seconds it wont fire up because it has no fuel
6 once your 30 seconds is up take each bottle and measure the amount of fuel in each make sure you label which injector the bottle came from.
7 the injectors should have pumped the same amount of fluid within 2ml of each-other
if you have a injector that is way less or way more then the others it is not pulsing right and you should clean it out then retest if it does it again after cleaning you ether have a bad ecu control signal or a bad injector typically its a bad injector. ***note you can watch the injectors spray in the bottle if its not a fine mist that may also point to a bad injector***
8 after this test is done just replace the injector o rings they are cheap and it always helps to have a proper seal
if you have a small vacuum leak at idle you would loose pressure but as soon as you hit the gas your pressure would spike and be ok again. i still think its a vacuum leak almost 80% sure that's whats causing your issue
Last edited:
combatmedic
Banned
This is the best way to do it. Especially when each injector is about 100 bucks.
Bad_Vision
Moderator
HEY 68 Wiskey
fuel injector 38$ RockAuto Auto Parts BOOKMARK THAT **** SAVES YOU MONEYS!!!!
thanks for the back up buddy:thanks:
Bad_Vision
Moderator
i do have one tip but its an old trick.
if you can get the truck to do its stumble thing open the hood up and take spray bottle of water start spraying your hoses focusing in on certain points if the stumble goes away when you spray a section then you may have found your leaking area.
but hose is cheap and its always a good idea to replace the hose every 5 years so its all up to you.
if you take each hose off one by one you can just cut the same length and replace it. no worrying about mixing it up that way
if you can get the truck to do its stumble thing open the hood up and take spray bottle of water start spraying your hoses focusing in on certain points if the stumble goes away when you spray a section then you may have found your leaking area.
but hose is cheap and its always a good idea to replace the hose every 5 years so its all up to you.
if you take each hose off one by one you can just cut the same length and replace it. no worrying about mixing it up that way
