Intermittent Stumble/Misfire?

LeeMajors

LeeMajors

New member
Hello all--

For the past two weeks I've noticed, only while on cruise control @ interstate speeds, say 65-75mph, I get an occasional stumble.

I feel it before I notice it on RPMs, just a brief stumble. The RPMs increase for a second and drop back to normal.

I haven't had any trouble starting or driving in any other conditions. Haven't noticed it off cruise control.

It feels like a brief misfire, but it never feels in danger of stalling or cutting off (say 2200 RPM, it briefly stumbles, jumps to 2300, then back to normal).

Plugs/wires done 10k ago. MAF cleaned 5k ago. No mayo under oil cap, no coolant burned. No smoke at startup or on acceleration. Acceleration and idle is totally smooth. It is not reproducible. I have a 45-60min commute and it has happened every other commute, once per. Happened twice this morning on the way in.

I've had a CEL nonstop for like 6mo (P0441) that I haven't fixed (bad purge solenoid) and I haven't yet checked for other codes.

Any ideas on where to start? Going to run some seafoam through my gas and see if it helps at all.
 
Register to hide this ad
I had a similar situation for years but with no change in RPM so this could be something totally different. I first noticed it towing at the crest of an incline, a brief twutch almost. It turned out to be my TPS. Only took about two years to figure it out....no CEL. I don't see seafoam used correctly, harming anything.

Sent from my SM-N900W8 using Tapatalk
 
ThorInc said:
I had a similar situation for years but with no change in RPM so this could be something totally different. I first noticed it towing at the crest of an incline, a brief twutch almost. It turned out to be my TPS. Only took about two years to figure it out....no CEL. I don't see seafoam used correctly, harming anything.

Sent from my SM-N900W8 using Tapatalk
Click to expand...

Yeah! Like a twitch. That's a really good way to describe it. And with CC I think it is adjusting itself to maintain speed.

What tipped you off on TPS?
 
LeeMajors said:
Hello all--

For the past two weeks I've noticed, only while on cruise control @ interstate speeds, say 65-75mph, I get an occasional stumble.

I feel it before I notice it on RPMs, just a brief stumble. The RPMs increase for a second and drop back to normal.

I haven't had any trouble starting or driving in any other conditions. Haven't noticed it off cruise control.
Click to expand...

Does it by chance only happen when you turn on your blinker to change lanes? Are you using LED brake light bulbs? I ask because a few years ago I had a similar issue with LED bulbs installed, but it would only happen when I hit the blinker and in my case it would cancel cruise. Swapped back to regular bulbs and the issue went away.
 
MONTYMTB said:
Does it by chance only happen when you turn on your blinker to change lanes? Are you using LED brake light bulbs? I ask because a few years ago I had a similar issue with LED bulbs installed, but it would only happen when I hit the blinker and in my case it would cancel cruise. Swapped back to regular bulbs and the issue went away.
Click to expand...

Nah, standard bulbs and its no correlation to signals.

Thanks for the thought though!
 
LeeMajors said:
I'm trying to avoid throwing parts at it (new baby girl on the way), but it does sound pretty similar.
Click to expand...

I think the proper way to do it is to record data as you drive. Mainly the tps since some stated that was his solution. When your feel the stumble, look at the data and see if the ecu saw any change in TPS at that time. If it did thats your problem.
 
Update:

Found a 2000 4Runner at my local pick-your-part place. Grabbed the VSV I needed to resolve the P0441 and a TPS for 15$.

Replaced them both.

After 250+mi no stumbles, no return of CEL. I know its early, but the stumble was happening 2 or 3 times a commute and it hasn't happened since the swap.

Seems TPS was the key.
 
I've been getting a slight stumble as well under heavy load along with my RPMs jumping randomly while coasting down hill. I read a different post about the TPS and now this one makes me believe that's a good place to start.
 
Check the classifieds. There is a member that sells or sold new OEM tps for $28 shipped. Not sure for what years however.

Sent from my SM-N900W8 using Tapatalk
 
Another reason is I cleaned the MAF and throttle body including taking it apart to clean. This made the problem subside for about 1 week before it came back.
 
You must log in or register to reply here.

Members online

Total: 246 (members: 1, guests: 245)

Forum statistics

Threads
278,309
Messages
3,554,071
Members
248,016
Latest member
Advally Service

Share this page

Trending content

Back
Top