Hey all,

Started happenin' recently. Only when driving (not parked or neutral), my FD ONLY hesitates at night when my headlights are on. Usually occurs mostly after in 5th gear for about a minute or two. Also, at night, the car will REALLY bog if I set my fans/ac/heater on to like setting 3 or 4. Never hesitates during day since headlights are not on. I figure it's something to do w/ the heavy load of accessories on mainly from headlights? I have to ground it since it sounds similar problem to the 3K issue. Anyone experience anything like this before?

Car idles fine and list of full mods are in my vB garage (click on signature banner below).

 

Aside from the basic recommendation of testing the alternator, cleaning and upgrading the grounds, I have to wonder if the electrical load system (see FSM F-135) needs inspection.

Dave

 

I have the SAME exact problem.

Happened a couple of months after my battery was relocated to the rear bin. I didnt notice it til it was getting darker earlier and i had to use the headlights. I was driving home from work and after about 10 minutes into the drive, the car would bog like its hitting fuel cut.

I havent taken it anywhere to have the stock grounds inspected although i got a new optima (yellow top) battery since my battery took a crap 3 weeks after that incident and i added 3 more grounds (4 gauge wire). 1 more to the battery and 2 more in the engine bay, alternator to body and uim to body. I havent checked it since as im afraid it will do it again lol. I should test it out now so i know if its a big problem or not.

My next drive, ill drive with the headlights/fans on to see if the problem is still there and ill let you know.

 

Like said above, your electrical load sensing system might not be functioning properly. If I recall, the control unit is on the passenger side by the ecu. (check service manual) Does the idle bump up when you turn on the lights or fans? Also, I didn't see what ecu you have? With the power fc you can monitor the battery voltage. What battery do you have? Aftermarket pullies? Underdriving the alternator too much causes problems. Stop boosting the car untill you fix this because you may not be getting enough voltage to the fuel pump.

 

Sounds to me as Dave stated to be your alternator. I dont know if this is true or not but maybe when your getting such a weak charge from your crappy alternator that it weakens your ignition spark ?

 

Yah, it idles fine when headlights and fans are on. Slightly idles 1-2 sticks/bars higher of course. Battery is a Sear's Diehard battery (...got earlier this spring). I have stock ECU and I believe pullies (though center pully seems to be upgraded by previous owner...looks newer..haha). I hardly boost other than after a long while to help clean out system. Car driven mainly on weekends if that info helps. Like someone mentioned above...I generally notice the car will stutter after about 10+ minutes of driving at night...normally when cruizin' in 3rd or 5th.

 

Yeah when i turn the fans on (even in day time), the idle will increase to about 1000rpm (750 without fans). But even though, this has been happening WAYYY when i first got the car. The hesitation only occured after the batter relocation early this year. I have the stock ecu as well.

I hope the grounds i added are sufficient, otherwise i might have to take it in to have it checked.

 

Had the same problem on mine. I just cleaned the stock grounds and added an additional 4 grounds. Worked ever since and no more hesitation.

 

I had a similar problem, Hesitation, low-voltage when I hit the brakes etc.

Try adding more grounding wires from your negative battery terminal.

 

I once had a problem very similar, it ended up being the water thermoSENSOR and/or thermoSWITCH. I replaced both at the same time, both located behind the thermostat housing.

The problem was usually triggered when the lights were on the EL Unit came into play. The ECU somehow got mixed signals and dumped too much fuel causing the bogging...

Let us know.

 

I assume the check engine light isn't on? So is the main pulley stock or aftermarket?