Ive got a 91 4runner with a 3vze auto fires up fine and idles and runs great till its warmed up
all these parts are new within the past couple weeks
new fuel pump (was out)
fuel filter
fuel pressure regulator (wasnt working)
coil and the other thing behind it (cant think of what that is)
plugs
wires
cap
rotor
valve cover gaskets
plenum gastet
pcv valve
maf

things ive checked
screw driver on 3 injectors all working (others I took out and tested)
checked timing set to about 10 to 12 degrees btdc
even checked the cold start injector
tps dialed in

Now the weird thing is after it warms i can unplug a spark plug wire and seems to idle fine doesnt matter which one so I tried 2 and bogs down and dies I am going to a compression check right now to see where that stands.

I pulled the timing cover off thinking it jumped a tooth on the cam nope still right on...

any other thoughts that I didnt think of?

 

just did a compression check and its
1.160
2.160
3.160
4.155
5.160
6.160
they are +/- 1 or 2 but that shouldnt be my problem there is still no codes...

this is really stumping me I am really at a loss the plugs are a lil black meaning that is running rich if im not mistaken... the o2 sensor is brand new also forgot to throw that in and there is no cat if that makes a difference.

the best way to describe this is first start runs fine then after letting it warm up just bogs seems worse in a gear like its going to die goes from 50 rpm's to 500 rpm's and when i tap the gas it bogs worse then i release the gas it idles back to 500 to 800 rpm's... Its almost like not getting gas but it squirts everywhere lol (found the hard way when my girl cranked it)

Anyone...

 

Unplug the vacuum hose to your EGR & see if that solves the problem.

 

I will try this asap thanks for the tip I will let you know

 

Did not help one bit and just a quick question how does the egr effect idle? You would probly think distributor or tps. I was just wondering how the egr effects it... thanks

 

Sorry if that sounded smart ass did not mean it like that...

 

any word on your problem?I seem to be having a similar issue

 

If the egr is coming on all the time or stuck open, it will cause a bad loping idle.

Check the intake tube VERY CLOSELY for any cracks. What you initially described sounds exactly like an unmetered air leak (vacuum leak). However, the unplugging of plugs with no effect is strange considering compression is good & injectors all work. The only other thing besides vacuum leak might be a clogged fuel rail.

 

i have a similar problem with mine where i have no change in hesitation if I pull #1 spark plug or leave it plugged in,I can hear the #1 fuel injector ticking but plug has no smell of gas or being ignited.

 

I will check the intake tube very closely and that what I thought but it only gives it a bad idle and crappy running after it warms up...

 

Well, many times it will mask an unmetered air problem when cold because the engine is running richer...

 

Ok so went over every inch lol no cracks but pulled the vacuum hose off the egr and no change in idle at all im pulling the plenum off off again to look for anything starting back at square 1 I guess

 

I am going to post every step that I take and how I do it so if I do something wrong someone can correct me
So I poured water on the tubing for intake and nothing its sealed so that's not the problem

I started pulling the plenum off and noticed that 90% of the vacuum tips were cracked (my buddy took all those off last time it was off) so going to be replacing a lot of those hoses and its not the small ones but the bigger ones. I have heard of a propane trick (unsure how reliable it is). But after I hook everything back up I'm going to try this to see what happens (NO SMOKING HA HA) I did notice these wires and box thing I have never seen this set up before I will post pics and I need some help with that. Also when I bought this 4 runner had a wire going from the wire harness on the passenger side engine bay behind the battery to a wire on the relay above the ecu (main one cant think of the name) some bare wire showing both ends going to cut and add heat shrink on those.

I unplugged the vacuum hose on the fpr and it started bogging down so I know that still works.

Checked wires on fuel pump and checked fuel lines no leaks and when I do crack a line its sprays all over in my mouth.

Now on the tps I was really unsure about cause I did this by what my buddy told me to do does any one have a link to set this with a multimeter?

I will continue to keep this updated after i get through some more of taking the plenum off and stuff like that.

 

also would you think it would be worth my while to do head gasket while i have it apart that far I have no history on this truck so I was thinking of just going through everything this time around and the reason why I would do the head gaskets is because aren't these head gaskets known for going out? and I would do the timing belt and water pump also might as well right? what are your thoughts the compression is 160 almost across the board

 

Anyone have suggestons on this

 

I had a similar problem recently and it turned out that one of my injectors was only putting out a fraction of what it should.it felt like a wet distributer stutter.pulled spark plug wire and it ran the same.i thought I had a dead cylinder,no spark or a valve issue.turned out to be a clogged injector.got them all cleaned and it runs like a champ