zebra1550

I have noticed recently that my 4Runner has been running a little strange. My wife has a bad habit of just starting up the 4Runner in the morning and quickly driving away. On several occasions over the last month, I have heard the RPM's surging really low when she does this. It sounded as if the truck really wanted to die. I've told her just to let it idle for a 20-30 seconds before she leaves so that the engine can stabilize.

Anyway, yesterday we were leaving the Home Depot and the truck started acting up. The engine was hot when we went inside, and we were not in the store very long. I started up the truck and began to back out, when I noticed the engine idle was at about 250 rpm. Once again the truck felt like it wanted to die. I let it idle for about 15 seconds, then drove away. Every time I would hit the brakes, the RPM's would drop really low, 250-500ish. Then the engined died completely as I stopped for a stop sign.

For the life of me I can't figure out what it could be. The truck has only been S/C'd for 8 months and 7K miles. It has the 7th injector and a Walbro fuel pump. I just recently put in one step colder Denso platinum plugs and also did Seafoam about 1 month ago. The PCV vavle is new and I cleaned the throttle body 8 months ago during the install of the S/C. I run a stock toyota filter so It can't be a dirty intake sensor. Overall the truck only has 42K miles on it. The truck hasn't popped a check engine light either.

Any help would be appreciated. I tried doing a search on low idle, but most of what came up was for the 3.0 engine. Maybe I need new plug wires? It also seems like the cold has brought this condition on. Maybe the one step colder plugs are too cold?

FilthyRich

could be a closed loop idle problem. Drop Gadget a line. He is the best resource for s/c diagnosis and troubleshooting. It really sounds like a tuing issue. another thing to keep in mind is the change in seasons. 8 months ago the weather was one way, now it is winter. Just a thought.
p.s. do you have an additional injector contoller???

bamachem

Check all your vacuum hoses. It sounds like you're sucking in some air after the MAF sensor and leaning it out. My gas mileage has been terrible lately, but I didn't have a CEL. Even so, I figured that it was my front 02 sensor beginning to crap out. I replaced it, and the MPG's didn't go up. I started snooping around under the hood last night checking vacuum hoses and found one loose. It was the large 1/2" one that hooks to the engine near the firewall behind the SC. It leads to the intake just before the throttle body. Anyway, it was COMPLETELY off, allowing the engine to suck in some serious extra air. I put it back on and zip-tied it to make it nice an tight and now it runs MUCH better. Hopefully, the MPG's will go up from 12-13 back up to 18+.

zebra1550

Thanks for the help from the both of you. No, I don't have an injector controller. I think that maybe the colder plugs might be fouling in the cold weather. However, I am going to check all of my hoses as bamachem suggested. I think zip ties would be the way to go. It funny just how loose some of the hoses are. I also thought about the O2 sensor as well. The extra heat from the S/C might have taken it's toll, but them again my O2 sensors only have 42K miles on them. The truck seems to be running fine for the moment, but I plan on going through it tomorrow. Thanks for the help, and I'll let you know if I find anything.