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Surging, pulsing while driving

239K views 271 replies 46 participants last post by  alexdowns288 
#1 ·
I have been havign this ongoing problem, but it has never annoyed me like this. My car surges and pulses during acceleration. Not during the whole acceleration, only when i apply more gas and the rpms rise, usually once i back off it stays steady. It also feelsl ike ive been getting less power in higer speeds. The car idles and drives perfectly at slower speeds but on the highway you can really feel the pulses and hear the exact making sounds. The only way to get the pulsing to stop is to give the jeep more gas.

My knowledge:
It sounds to me like its a missfire somewhere along the engine due to the fact that the exhaust is making sounds from the pulsing. Sounds like maybe one cylinder isnt firing like it should be.

Last year the check engine light was ignited and gave a reading for cylinder 1 misfire. I did the following but could never pinpoint it:

-Chnaged spark plugs (put in crappy autolites
-Chnaged cylinder 1 fuel injector
-Changed idle sensor in throttle body
-Chnaged coil on cylinder 1

No matter what i chanegd the light would not turn off, until i seafoamed the crankcase.

After about a few weeks after pouring the seafoam in i noticed the light turned off and never returned.But the pulsing still remains, but it has never been this bad. The manager at aamco looked up my vehicle and said they were prone to excessive carbon on the valves and the seafoam would help.

But there has to be something else with the vehicle wrong for it for it to be pulsing like this, with no check engine light on. I am so frustrated because i dont want to spend money on parts i dont need.

The one thing i am thinking of changing is the sparkplugs to the NGk ones. The autolites have let me down in a few other cars.

Any help would be greatly appreciated :):)
 
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#2 ·
I have the exact same problem and mine is the same year/engine, but I havent noticed sounds from the exhaust. It does it the worst around 40mph. I have no clue what it is, but im wondering if it could be the TPS. Very annoying though.
 
#124 ·
I also have this problem, and mine is also the same year/engine. Mine is also worst around 40mph while trying to hold a steady speed. I havae noticed that mine is worse when running the A/C.

I also seafoamed mine recently and got absolutely zero smoke. I do think it idles and runs better though.
 
#4 · (Edited)
ddi you get a ton of black smoke when you used seafoam? that would come from the carbon build ups
Well the last time I added it was a couple months ago, then got an oil change and just added it yeserday. I would assume it takes alot of time for the carbon to burn off.

Also how would you diagnose the TPS? and it sounds like a cylinder is not firing correctly due to the exhaust sound. It is a pulsing sound comming from the exhhaust and can also feel. Then when looking at the rpms you can see them pulsing too. Thats why i believe its something to do with the ignition of a cylinder. But im not really sure.

And the only reason i probably can hear it is because I have a magnaflow exhaust, which is probably more audible.
 
#6 · (Edited)
Havent really noticed any smoke, i pretty much added it and then drove about 10 miles. But would seafoam burn even if it was added to the oil?

And another thing to add, sometimes when i come to a stop the trans hits a little hard. But was tested by aamco and the trans is perfect. I read on another post the Throttle Position Sensor could affect this too. Should i just change the sensor and hope my overall driving is better?
 
#8 ·
Why would i put the seafoam in the brake line. I have no problems with the brakes. And the crank case is the oil!. it says put half the bottle in for the amount of oil i have, and i put the other half in the gas.
 
#10 ·
I put about 1/3 can in my brake booster about 6 months ago and got zero smoke, I was very bummed...im gonna give it another go when it warms up.

Regarding the TPS I have no clue if that is it or not with mine, but im considering swapping it out bc the part is only like 30 bucks
 
#11 · (Edited)
It's going to surge/buck regardless what you do because of lack of power and tunning. I've done EVERYTHING a long time ago to get down to the bottom of this issue and no results.

However, it did get better, but did not go away, after I installed the larger tires and 93 octane tune.

But as for me, nothing I did resolved the issue. Nothing.

Seems as if the only thing that will make it go away is a custom TCM tune but the 3.7 and 6.1 TCM can not be tuned with aftermarket tuners. That's only for the 4.6 and 5.7

Edit: Let me just say mine is going to buck/surge regardless what I did. I just had to adjust the way I drive it at certain times. It mainly did it going up hill or at around 40 mph at 1300 rpms.

Just like the WK2 guys with the 3.6 engine. They are experiencing something similar with having to adjust the way they drive due to lack if power and not so good tuning.
 
#12 ·
It's going to surge/buck regardless what you do because of lack of power and tunning. I've done EVERYTHING a long time ago to get down to the bottom of this issue and no results.

However, it did get better, but did not go away, after I installed the larger tires and 93 octane tune.

But as for me, nothing I did resolved the issue. Nothing.
I thought I had it solved when I swapped my O2's, but I was wrong :mad:
 
#13 ·
This is why I'll never purchase another underpowered auto again. Never.
 
#24 ·
That is why I got the hemi, had jeeps all my life always got the smaller engine was not going to this time. Back to the problem sounds like a spark plug problem, get the oem spark plugs see if that helps. On the hemi engine you got to us the oem ones or the engine drives like shit.
 
#16 ·
Just Posting an update:

Today i did the sea foam treatment (Oil,Gas, and vacuum line,) And i also changed the plugs from the crappy autolite coppers to Bosh Platinum.

The car runs and idles a lot better then it ever has. But i believe i still feel a little pulsing while accelerating slowly. Next I will change the TPS just because it sees very easy and the car has 110,000 miles on it. Probably won't be changed till next weekend, but will keep you guys posted.
 
#17 ·
I'm pretty positive that the issue can not be solved. At least I wasn't able to solve it after spending a chit load of money.

Good luck though and I will applaud if/when you do solve the issue.
 
#18 ·
Okay guys, sorry for posting on an old thread>

Just bought the Throttle Position Sensor from auto zone (actually had one in stock) and will install on thursday. Let you know if it resolves the problem completely.
 
#19 ·
Let us know.
 
#21 ·
Im not sure if the torque converter is the problem, It sounds like the problem is from the actual engine due to the noise the exhaust also makes. Will let you know on thursday if my problem is resolved :). But it has been a lot better since last week, took the crappy walmart spark plugs out and got a set of bosch platinum plugs and ran sea foam through the vacuum line and the problem practically went away!!! Only on very rare occassions do i even feel it the slightest, but its barely noticeable. Also it has restored so much power to my jeep!
 
#28 ·
Ok guys just an update on the situation:

Today I ran sea foam through the vacuum line correctly, waited 20 minutes and got tons of white smoke!! I also replaces the throttle position sensor and reset the cars computer.
 
#30 ·
Okay so after replacing the throttle position sensor, resetting the cars computer and sea foaming! the problem still does exist, so you don't need to change the tps! its so frustrating how this still happens and no codes! the jeep drives perfectly except this annoyance, although it is barely noticeable I am a daily driver and pretty OCD about my jeep! I hope eventually I can find a solution. I just wonder if it could be a coil or something with the fuel pump.....
 
#33 ·
Thanks! It was horrible on my 200 miles trip on the highway pulsing the whole way! after i put in some better spark plugs + sea foam the problem is a lot better! but still can be quite annoying..

Does your problem happen when the jeep is accelerating and u feel a pulse? then if you give it some more gas it will go away?
 
#35 ·
Same for me!!! It doesent happen all the time! Some times it drives great other times its bad! Can you hear the pulsing in your exhaust? And if its bucking my gfs car would buck and when you gave it more gas sometimes it didn't do anything! The problem was a cracked sparkplug. But my problem got a lot better after new sparkplugs. The only thing I can think of is to change all the coils. But that would be expensive especially because I have no check engine light!
 
#36 · (Edited)
i have/had the same issue. after plugs, egrs, vacuum leaks fixed, it still does it. there is a "dead" spot in the accelerator at around 1700 rpms. i have noticed mine only does it in overdrive, and not when i put it in 4th. it appears to be an overdrive problem. i did find that if i reset the ecu it gets better for a while, until the ecu relearns my driving habits. i also notice it got a little better when i topped off my tranny fluid. but it never fully goes away.
 
#37 ·
Were you getting an codes thrown for the vacuum leak? Mine does it in 3rd + and is very annoying pulsing and won't go away until i give it more gas and its a temp fix. I wish i could figure out what it is...
 
#39 ·
What the of plugs did you put in? i at first had autolite's from walmart lol and they were suppppppppper crappy. Now i switched to bosch platinum from auto zone and it started running a lot better. I just with my car was throwing codes so i knew that to change...........:confused:
 
#41 ·
Good Choce! i Also mistakenly installed the automates into my Girlfriends mustang and the car didn't run well at all!! Then i switched to the oem motor craft plugs and it ran beautifully with no codes at all.
 
#45 ·
Just an update... My problem is getting very bad. I will just be cruising and it will start pulsing if I have to go up a hill or needs more power. Then I have to push in the gas pedal very far in order to get it to stop. Almost to the point of accelerating rapidly. Dead spot in the throttle almost. Then I also get a vibrating sound when it pulses, almost like a cylinder is knocking. If I can't find solution I have to take it into a mechanic.
 
#47 · (Edited)
Lazy O2 Sensor(s), Cat(s). going bad, MAP Sensor, in that order???
 
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