4.7 ltr 2WD starts fine and while cold runs fine. Seems after an hour or so of driving the engine begins to skip. Will idle just fine but when giving gas the engine skips and refuses to accelerate beyond 1700 rpm. Had the cats changed 6 months ago. someone suggested the MAF sensor might be bad....so cleaned it. Still runs rough. I suspect it might be a sensor. If I leave the car overnight ...runs fine in the morning. Engine gets hot....begins to skip and cannot accelerate unless going down hill. Vehicle skips especially when under a load.

Does the MAF sensor have anything to do with this? Maybe it could be the Engine Coolant Sensor? Not sure what to do. Don't want to throw parts at it without some idea what is causing it. BTW...no check engine lights at all. And nothing showed up on the computer when it was running rough. Tech told me cylinders 2 and 4 were not firing properly but immediately after cleaning the MAF sensor the car ran fine for 4 minutes then problem returned Please give me some ideas here. Thanks, Jeff in Canton

 

2WD? The GX is full-time 4WD. Is this a 4Runner or Sequoia?

If #2 & 4 were misfiring, a code should have been set (OBD-II is pretty good at detecting them). I would pull those spark plugs and take a look.

Chip H.

 

This is my Sequoia (2004 original owner with 241,000). I also have a 96 Lexus LS 400 and found lots of good help on the forums here. Hence why I am seeking assistance here.

Can'f find any codes. Last codes were in May and said bad cats. Had the cats replaced and codes clearned and no codes since. Has not run correctly in a year. Not sure what is wrong with it.

I pulled the plugs and replaced all in the last 6 months.

 

I would look again. Perhaps they became loose.

Chip H.

 

New OEM coil packs and plugs will be here tomorrow.....will go from there.