Have a 2002 Toyota 4runner, I have had an issue where I will be driving at a constant speed and then all of a sudden I intermittenly loose power. So I back off the pedal for 3-4 seconds and ease back on it again and it takes off. Then it may happen again, no specifac intervals, just randomly. Or sometimes while im at a light I hit the gas, it doesnt go, sputters a few then gives power..

Seems to happen more later in the day rather than first thing in the morning. Suggestions/where to start?

 

Spark plugs, PVC valve, spark plug cables, air filter vacuum hoses/vacuum leak are a few places to initially look at. Possibly a fuel injector that is acting up.

 

Had similar issue in a 2000. Ran without proper diagnosis for a long time and started giving a CEL (not sure which code, now) 100% solution was a dirty mass air flow sensor (unknown reason for the dirtyness). This was my dads truck and the cleaning was done at a shop so i am not sure what it involved, but it was not difficult. Hope it helps!

 

TPS, MAF, fuel filter, etc.

Any codes/Check engine light on?

 

Changed the fuel filter, albiet awhile ago..this problem hass been occuring. So I went after that first, then I cleaned the mass airflow sensor with a specific cleaner designed for it. I do need to do a tune up, so I am going to start with plugs and wires. I found a great pictorial on the plugs. I will start there, in the pictorial it looks like you remove some of the air intake to get in there..i can inspect the throttle body too that may be dirty.

No error codes, I changed the O2 sensor since I just moved to Texas and had to get it inspected. It ran fine for awhile, so I thought that may have been it but it started acting up again.

 

I had the same problem start happening about a week ago. Pretty bad hesitations happening while driving at any constant speed, and occasional hesitations when accelerating from a stop. No CELs. I put new plugs in, and found that the old ones were not very tight. Almost loose enough that I could remove them with my socket extension by hand without the leverage of a ratchet. After putting in the new plugs, it's running like new again.

 

Did you use a stock replacement like a denso? or did you cheap out and get a bosch or other aftermarket o2 sensor? I've seen bosch sensor's cause issue's such as missfires and lean codes, so this may be a possibility for you.

 

I had this happen with my 02 also --- seemed to be somewhat related to hot weather.

I traced it back to heavily oiled K&N filter --- cleand the MAF sensor and lightened up on the oiling of the filter and all has been well. It did take a little while to get the oil 'residue' flushed out of the box and air tube, I think it took several sensor cleanings as well.

 

good info thanks