Just picked up a 91' 4 runner with a 3.0 . I went to do emissions this morning and while trying to hold rpms I discovered a surge that starts around 1600rpm and goes away after 2600rpm or so. This only happens when revving with no load. Under load its fine. This is my first 3.0 so any tips on where to start are appreciated.
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3.0 surge 1600-2600 rpm, no load
- Thread starter lethe
- Start date
CHOP SHOP
Well-Known Member
see if depressing or releasing the brake pedal makes a difference.
That was the first thing I tried. It only surges between those rpms with no load. Just sitting abs idling its perfectly smooth at 8-900rpm. One thing I did notice was the silicon around the cover plate on the maf looks like it may have been removed. I don't know if the maf would effect a small rpm range like that though.
WA-Wheeler
Well-Known Member
Coolant temp sensor?
That's kind of what i was thinking when i found out it is fine until the engine is warmed up to operating temperature. It still seems weird that it would only effect it in a small rpm range and only while revving out of gear.
Replaced coolant temp sensor with no changes. I was replacing the passenger side valve cover gasket and found the intake elbow from the throttle body to the silencer? was badly cracking and has a big piece missing. It's bad enough that even duct tape can't bandage it. Not sure if replacing it will fix the problem but it sure as hell won't hurt.
Replaced the fubar intake boot at the throttle body. It didn't make a difference in the surge but at least i know it's not leaking there anymore. After seeing someone in Mavericks thread mention unplugging the tps i gave that a try and the surge went away. So either i need to replace the tps or try readjusting it.
Maverick26
As iron sharpens iron...
Sounds like the same deal man... the buddy that owns the truck is going to bring it over tomorrow and we are going to swap his TPS for mine and make sure it runs good cause a new TPS is like $80 he said. Being an electronic part most parts stores wont take it back.
