Intermittent Stumble

This summer I was driving my wife's 02 V6 Highlander and all of sudden it had no power and felt like the engine was stumbling, I press the gas and it seemingly would not accelerate. This lasted maybe 10-15 sec and then all of a sudden the power came the engine down shifted and took off (my wife initially yelled at me for accelerating hard). It seemingly didn't happen again, I assumed it may have been bad gas.



2 days ago it happened again, it last for 5 secs and then the power came back. I mentioned it to my wife and she say this has happened 3 time this past week to her, including last night. I am not getting a check engine light or any codes store, my initial thought is that maybe a fuel pump but I am only guessing. Anyone else had this problem and what was the solution?

Reply 1 : Intermittent Stumble

Have you checked your fuel filter?

Reply 2 : Intermittent Stumble

Definitely tune up and troubleshooting time. Without knowing your history of maintenance, it could be ANYTHING.



Air filter, fuel filters, spark plugs, fuel injectors, vacuum leaks, bad sensor........

Reply 3 : Intermittent Stumble

Quote:

Originally Posted by TrailDust Have you checked your fuel filter?

I thought Highlanders did not have fuel filters. or is only my '04 that has the mesh sock in the tank, and the older Highlander had a true fuel filter??

Reply 4 : Intermittent Stumble

Try some techron concentrate (not the cheap techron) fuel treatment first. Two bottles treating two tankfuls back to back. Make sure your air filter is clean. While you have the air cleaner out take a look at MAF and throttle body also - may need cleaning.

Reply 5 : Intermittent Stumble

Quote:

Originally Posted by shortlid I thought Highlanders did not have fuel filters. or is only my '04 that has the mesh sock in the tank, and the older Highlander had a true fuel filter??

As I understand it the 1st Gen Highlanders have a fuel filter located in the fuel pump assembly.

Reply 6 : Intermittent Stumble

My Highlanders History is that has 81K miles and I did the spark plugs and air filter at 75K miles (started getting a rough idle). The throttle body was clean when I did the plugs, I think I sprayed the MAF with throttle body cleaner, but I can't remember (I did that atleast on one of my Toyota's last year.) I don't have any check engine codes. My only mechanical problem I have had beside brakes and exhaust is stuck open thermostat last year. I doubt I have a vacuum leak.

Reply 7 : Intermittent Stumble

Just on th eoff chance that its dirty injectors or a fuel varnish problem somewhere in the fuel delivery path I'd try the techcron concentrate for a couple of tanks of gas. Also if you are not using top tier gas - you might try switch to using only top tier gas.



http://www.toptiergas.com/retailers.html

Reply 8 : Intermittent Stumble

Quote:

Originally Posted by jabberwock Just on th eoff chance that its dirty injectors or a fuel varnish problem somewhere in the fuel delivery path I'd try the techcron concentrate for a couple of tanks of gas. Also if you are not using top tier gas - you might try switch to using only top tier gas. http://www.toptiergas.com/retailers.html

I always use a brand name gas (top tier). I usually run a couple tanks of high octane through the year as well, but my wife mostly fills up with 87. I will try some techron cleaner. We don't drive her Highlander all that much about 5K miles/year (the last 4 years) but it does get used on weekends for atleast driving around town. I don't know if the infrequent use playing a factor.

Reply 9 : Intermittent Stumble

You might have got a tank of bad gas. Has the problem persisted thru multiple tanks of gas?

Reply 10 : Intermittent Stumble

Quote:

Originally Posted by dgoodhue My Highlanders History is that has 81K miles and I did the spark plugs and air filter at 75K miles (started getting a rough idle). The throttle body was clean when I did the plugs, I think I sprayed the MAF with throttle body cleaner, but I can't remember (I did that atleast on one of my Toyota's last year.) I don't have any check engine codes. My only mechanical problem I have had beside brakes and exhaust is stuck open thermostat last year. I doubt I have a vacuum leak.

You made sure that vacume lines going to air filter box were re atached correctly?

Reply 11 : Intermittent Stumble

Quote:

Originally Posted by jabberwock You might have got a tank of bad gas. Has the problem persisted thru multiple tanks of gas?

The first time it happen was maybe 3-4 tanks ago, but the recent incidents have been on the same tankful.

Reply 12 : Intermittent Stumble

Quote:

Originally Posted by shortlid You made sure that vacume lines going to air filter box were re atached correctly?

Yes, I am 100% sure they are all connected. I got a code this spring that was because my wife didn't tighten the gas cap, and I went through the vacuum lines prior to that, trying to point the problem, before realizing why I was getting that code.

Reply 13 : Intermittent Stumble

My wife's '02 4WD Highlander w/78k miles has had the same problem. We had the IACV replaced a year ago, and it seemed to go away for a while, but it just started the occasional stumble again. My wife usually runs 89, but sometimes 87. We had the injectors cleaned about 15k miles ago, and it has anew air filter.



Any luck diagnosing yours?

Reply 14 : Intermittent Stumble

Quote:

Originally Posted by PA_Highlander Any luck diagnosing yours?

No luck. Shortly after I made this post, my wife had some more stumbling on a long highway trip. However since that time, it hasn't happened. Basically it hasn't happened since its been really cold out. Maybe it was that tank of gas or perhaps the cold weather is masking the problem. My intutition tells me its the fuel pump.