hicup in my 4runner
 

My name is Matt, I'm 17 dont know too much about cars but I know the basics. I bought my 1995 3.0 v6 4runner in late july of 2012. After a few months my head gasket blew and that happened to be a recall for the year. My dad and I replaced them. A few months ago I noticed while I was driving that my rpms were dropping randomly then picking back up almost like a hicup. I thought it could be my injectors getting clogged so I put a new fuel filter in and some fuel system cleaner. That wasnt the problem. I have no vacuum leaks. My diagnostic plug in the engine compartment wont let a computer tester read my computer. If anybody has had the same problem with their 95 4runner please help.

FSM link

Check and adjust your idle speed would be my first suggestion, if your idling high it will trigger the fuel cut off. This will happen when you turn the steering all the way or step on the brakes.

Vacuum leaks are a possible cause, spray carb cleaner at the hose connections and along the vacuum lines. Any idle change indicates a leak that needs the hose reseated or replaced.

Once your sure all the vacuum lines are sealed, perform the brake booster, power steering, and AC idle up inspections. These tend to cause a rise in rpm not a drop so those are unlikely causes, but they're still vacuum leaks :D

To read the diagnostic codes you only need to connect the two terminals, spare bit of wire or a paper clip is all you need. Diagnostic codes are listed under the engine section of the manual.

There are trouble shooting charts listed in the engine section of the manual also, nice step by step numbered check this then this directions.

my idle is at the right spot, ive checked for all the vacuum leaks. the only thing I havent done is the diagnostic codes, Ill have to check into that and see what it comes up with

This sounds exactly like what I had going on with mine. Chased everything far and wide and it ended up being a ground that disconnected infrequently, occasionally causing a complete drop in my rpms for just a second, then back to cruising speed, like a hick-up.

The ground he'ss talking about is presumably the ground for the igniter. Not sure where that is offhand on a 3vz engine, should be easy to find follow the coil wire off the distributor. Make sure everything is clean and tight there.

Thank you CO, this was a while ago so I cannot remember exactly where I did the rewiring (I had a lot of things apart at the time). It was definitely the igniter ground, though. The first time I felt the hick-up I was cruising at about 70mph and if felt like the thing stalled, but then came right back to life (gone for <1 second I'd say). The next time it happened (months later) I was in cruise control, around 70mph again I would guess, and I could not hear a difference in the exhaust not while everything cut out (still flowing?) but when it came back there was a big "whoosh" of my loud intake. This happened a few more times around town, and since I knew it always came right back to life I wasn't too worried so I just chased things down gradually. Eventually coming to my not-well-grounded igniter. I'd love to tell you what wire did the trick, but I replaced A LOT, knowing that it would be good considering my future engine swap.

i did try the diagnostic test and my check engine light blinked like nothing was wrong. so now i will deffinetly track down the bad ground from the igniter thanks for the help. will post a follow up to let yall know if it worked.

where is the igniter at on the 3vz? and is it a long process or a quick and easy repair?

I wish I could recall for you but I'm stuck on my phone at work. Take a look in the factory FSM (search for links if you don't have it). Did my explanation sound like your issue? Or rather did it make sense lol? I feel like it's really hard to explain cause it doesn't really make much sense since everything keeps working...and I just saw that CO_94_PU already linked the FSM...

I doubt it is the same problem, ignition cut out is a big difference compared to a slight drop in rpms.

As I mentioned the ignitor and coil are at the end of the coil wire off the distributor, probably on the fender area.

What is your idle set at? How did you check for vacuum leaks?

I did find the ignitor, it was on the fender but I can't tell which wire is the ground because the all feed into a tube that has the ignitor coils wires and other ones in it taped together. do you think it could be my ignitor as a whole going bad or should I just replace the wires and harness for the ignitor. My truck idles at about 700 rpm when running correctly if that's what you mean Co. My uncle and I sprayed wd-40 and waited to see if the engine bogged down a little but it didn't have any leaks.

Also I wouldn't be surprised of it was the ignitor because the description yotasavg said sounds very close to mine but it does it in closer time frames than his did. Any good places to order a new wire harness for the ignitor btw savg?

At the worst of when this was happening it was pretty frequent... It wasn't just the couple times I mentioned, those were just the first couple times I felt it. I always get my parts from rockauto, but in this case I paid a buddy that likes wires a case of beer and we got it done together. I'm not really sure what's available, it didn't even cross my mind to get a harness just for that to be honest with you..

Did you just install new wires with the existing wire harness savg?

And I will check on rockauto to see all my choices