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-   -   Surging, pulsing while driving (http://www.jeepgarage.org/f181/surging-pulsing-while-driving-37235.html)

Madanio24 02-13-2012 09:02 PM

Surging, pulsing while driving
 
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 :):)

Bleeding Blue 02-13-2012 09:05 PM

Re: Surging, pulsing while driving
 
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.

SvenskaJeepGuy 02-13-2012 09:33 PM

Re: Surging, pulsing while driving
 
ddi you get a ton of black smoke when you used seafoam? that would come from the carbon build ups

Madanio24 02-13-2012 10:38 PM

Re: Surging, pulsing while driving
 
Quote:

Originally Posted by SvenskaJeepGuy (Post 573360)
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.

SvenskaJeepGuy 02-13-2012 10:47 PM

Re: Surging, pulsing while driving
 
U should have got about 10-20 min of black smoke after using seafoam

Madanio24 02-13-2012 10:50 PM

Re: Surging, pulsing while driving
 
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?

SvenskaJeepGuy 02-13-2012 11:13 PM

Re: Surging, pulsing while driving
 
you are supposed to put it in your gas, oil and brake booster line and wait 20 min. then start your car and keep the rpms up. is should smoke like hell for about 10-20 min and stall out a few times. mine ran like a champ after that.......

Madanio24 02-13-2012 11:18 PM

Re: Surging, pulsing while driving
 
Quote:

Originally Posted by SvenskaJeepGuy (Post 573453)
you are supposed to put it in your gas, oil and brake booster line and wait 20 min. then start your car and keep the rpms up. is should smoke like hell for about 10-20 min and stall out a few times. mine ran like a champ after that.......

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.

SvenskaJeepGuy 02-14-2012 03:16 AM

Re: Surging, pulsing while driving
 
Quote:

Originally Posted by Madanio24 (Post 573458)
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.

its the vacuum line that is connected to the brake booster............. sorry i thought you knew a little about it, thought you would have researched it prior to putting it in your vehicle.

Bleeding Blue 02-14-2012 06:47 AM

Re: Surging, pulsing while driving
 
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

lll2for3lll 02-14-2012 06:56 AM

Re: Surging, pulsing while driving
 
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.

Bleeding Blue 02-14-2012 07:00 AM

Re: Surging, pulsing while driving
 
Quote:

Originally Posted by lll2for3lll (Post 573621)
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:


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