02 Tacoma 2.7 Rough and Low Idle

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!

 

Yeah I did hook up a reader and no pending codes.

 

Mine has coil packs, but I tried disconnecting each one of them one by one, but everytime I disconnect any of them the truck dies. I was thinking it would stay running on 3 cylinders, but I guess not. I thought maybe one coil pack or fuel injector was going bad possibly, but it seemed to do the same thing on all cylinders.

 

Yeah I did, it was 175, 155, 160, 175

 

it seems once my 2.7 is up to temperature it idles a bit rough and vibrates truck slightly at rpms around 600. ive done everything you have except the iac and tps yet no difference either.

it seems this is just what these engines do as i have read other accounts of this. ive only had my truck for 8500 miles so cant say if it did this when it was young but its never died or felt like dying even when i sometimes dont give it enough gas while engaging clutch. so i am content for now to live with it.

 

I know what mine felt like when I got it and it was smooth as ever. I have heard that the 4 cylinder can idle a little rough, but knowing how mine did is what bothers me the most...lol

 

My 2000 tacoma (now my sons) just started doing the same thing. I did the same, checked all plug wires/plugs one at a time, all good. I do have a flashing check engine light now, is there anyway to check the code without a reader?

 

im not sure how to read codes without those handheld instruments or pc software. mine has never spit any cel but i think ive heard and read that a flashing cel is worse than one that is simply on and indicates a more serious issue. i could be wrong but id figure it out asap if i were you

 

I'm in the same boat as you only difference is a v6, knowing it was smoother is what bothers me. But with no codes and all looking good idk what to do

 

Yeah you and me both. I had one code when I bought the truck for an O2 sensor, but I replaced that and haven't had a code since. I almost wish I had a code. It would be a lot easier to fix. I wonder if a valve adjustment would help...I know thats not a fun job from what I have heard.

 

I got some creaking noise in my front left, I also kinda hope something would just give so I could fix it

 

Anybody with some other ideas besides the stuff most of us have already tried? Should the engine die unhooking just one coil pack or should it stay running? I would think it would run off three cylinders.

 

My '04 2.7 has idled at 750rpm in nuetral since it was new. Some vibration is going to be present w/ a 4-cylinder that big.

 

i drove an 85 4 cyl volvo in high school and the distributor messed up only giving spark to 3 cylinders and it would die if you didn't give it enough gas and instead just let it idle. 6 cyl would prob still run and i've seen a mustang 8 cyl run one down

 

Yeah I know a 6 cylinder would run off of 5, but wasn't sure on a 4 cylinder. I am just leaving the coil pack on the plug and disconnecting the wire from the coil pack. I just was wondering if anybody with a 2.7 could see if theirs would run off of 3 cylinders.