krue92

I know there are numerous threads on this, but I can't seem to figure out what to do next. I have a 02 Tacoma 4x4 with the 2.7L with 145k miles. I have had the truck for about 6 months and the first 3 months the truck ran great. Lately the idle has been low in drive around 600rpm probably. It seems kinda low in park too around 750rpm. And when its in drive it shakes the whole truck. The wierd thing is when you give it gas it smooths out and seems perfect throughout the whole powerband. I have replaced the plugs twice, cleaned the MAF, cleaned the throttle body and IAC. I then replaced the whole throttle body, IAC, and TPS with another used on, but that didn't make any different either. I checked for Vacuum lines and didn't see any cracks or disconnected lines. I checked the mounts as well. You can just feel the engine shake at idle, but it levels out and runs great. Its just driving me nuts and I just want it fixed, but I don't know what else to do. Also it is not throwing any codes at all either. I know how good it ran when I got it, so I know its possible to run like a champ. Thanks for any input!

yamaboy03

Mine is doing almost the same thing. Have you ever used seafoam through the system? I used it and about 8 months ago and now it's starting to have problems. Mpg in the city is now at 13.1. And my engine is running rich.

krue92

I haven't used seafoam in mine, but I did do a compression check and it was 175, 155, 160, 175. My mileage hasn't really changed a whole lot. I am still getting around 17-18 mixed driving and it is the winter months here.

Mrxixx

I just bought an 01 Tacoma 2.7 with a manual transmission that seems to have a similar issue. It happens most often when I have the vent motor on. If i give it a bit throttle even just momenteraly, it seems to clear up. I have cleaned a bunch of stuff on it, MAF and other stuff, but it remains. I have no clue as to what it's causing it.

85GT-79FJ40

What do the plugs look like in cylinder's 2 and 3? I would be concerned about the lower compression in those two cylinders. You could have a head gasket issue blowing between the two. Not much, but it wouldn't take much to affect the idle. Any oil or coolant consumption issues? Also just because you don't see any cracks in the boots doesn't mean there isn't a vacuum leak. It doesn't take much of a leak to mess with the idle. See if you can find someone to smoke test it to rule that out.

krue92

The plugs look great and look all the same in each cylinder. The coolant level is perfect and no oil consumption at all. The truck itself runs great except for the low/shaky idle. I will check the vacuum lines again. Thanks for the help.

tripz

Did you check your air filter? Make sure it's clean

Check the coil packs, if you feel a misfire. Did you check your timing? Idle air control valve might be a culprit too for the idle.

tantacoma

Shaking at idle could also be bad motor mounts.

krue92

I recently replaced the air filter. How can I check the coil packs? I have tried removing each one to see if maybe one is bad, but this always kills the engine. I haven't checked my timing, but not sure how that could get off if it was running good a few months ago. I did replace the IAC, but that didn't make a difference. My buddy who is a mechanic checked out my motor mounts, but said they were good. I'm just at a loss of what to try next.

krue92

Here is something I found interesting today. Its been very cold here and today it was like 45 degrees. I noticed my truck isn't idling as crappy now since its warmer out. Its still not perfect, but it is a lot better. I mean it has been idling bad probably about the same time it starting getting cold out. Never thought it could be related to the cold weather. Does this point more to something like a vacuum line or something else now?

tantacoma

Could be a bad intake temp sensor. On my 99 2.7, its integrated into the MAF sensor.

krue92

Yeah from what I read it is built into the maf as well. Would it throw any codes? I guess I could try replacing this, but is there anyway to tell if that is the problem?

Tyler Noble

did you ever figure out what happened with yours? I have the same backstory and issue with mine