Engine having issues.

2001 tacoma 3.4 prerunner 4 door. Runs good most of the time. No lack of power, no check engine light.

Problem= Very intermittent rough idle or sputter that sometimes leads to the engine dying at idle or as applying the gas from idle, Plugs white as if running lean, poor poor gas mileage. I am talking like 10-12 mpg and its not due to my foot

Attempts to correct= New plugs and wires, new air filter, fuel system cleaner.

What next?

 

Done. Being as it is so intermittent I figured it was not a vacuum issue but I checked anyways

 

Clean the MAFI as well, but white plugs show a lean condition.

I would look for a vac leak as well, seems like you have un metered air.

I have seen the vac line to the brake booster crack a few times on the 3.4L

Also check for cracks in the intake pipe after the MAF


Justin

 

I did check for vac leaks and I just took off the intake tube and it is good. I also just cleaned the maf. We will see if that does the trick. I had a 01 ranger and it got a vac leak at the booster. Never knew till i ran a stoplight with my brake pedal on the floor. Anyways I am leaning toward a sensor. just not sure what one

 

Any follow up on this? I am having a similar issue. Thanks!

 

Check the idle air control valve. could be gunked up and sticking

 

EGR valve.

 

Buzz and Steve. I know the idle air control valve. Would that tend to stick open or closed? Never id'd the egr valve. My truck used to start with an authoritative roar. Now it struggles to start.

 

There may be an opening under the EGR valve to stick your finger and push up on the diaphram. It should move freely. If it doesn't use a none petroleum based solvent (it wont destroy the rubber diaphram) to spray underneath up into the valve to free it up. Or just replace the valve. The valve doesn't last forever and is cheap to replace.

 

I plan to change the oil tomorrow. Oh how I love dropping the skid-plate for that I'll have a look at the egr valve. Hmmm... Decided to look around before posting this reply, since I've never seen it, and I don't usually miss much. Not sure I have one:

 

Oh... No Check Engine light, BTW, and I do have a 3.4L