Gremlin1802

Ok, well whenever I turn on my headlights, the car backfires and acts like it's missing. I tried searching, but I don't know where to begin. It's been doing this for a month now, but only when I have the headlights on. I'm thinking the battery/alternator isn't giving enough juice or something, but the PFC shows 13 to 14 volts all the time. I'm gonna feel dumb if this is something simple.

dinosaur

I experienced the same problem when I had the headlights on, or ran the a/c, the car would idle and accelerate fine, but running a constant speed (in traffic, or under cruse control) the engine seemed to miss. When it slowed enough to add more throttle it accelerated with no miss (lotta whiplash on long trips). I looked at O2 sensor (replaced twice) and it helped for a few hundred miles then the miss returned. Checked the alternator (read fine). My short tern work around was not run the A/C, or drive after dark, both sucked. I did finally cure the problem, and it sounds simple but the fix took 10 hours to complete, so don't feel stupid. I did a complete vacuum line replacement. A few were hard, a few were cracked, and one was off the connection at the rear of the lower intake. Car runs stronger than it has in a year (tires break loose in third when the second turbo comes on), fuel mileage is much improved, and no more miss (except the old 3000 rpm stumble). I don't know of any way to troubleshoot these lines to be sure it will help you, but if you haven't replaced the OEM lines with silicon hoses, think long and hard about it. I had an experienced Maz fanatic help me and it took 10 hours to complete (a lotta stuff has to come off to get to the rats nest), or a good shop should be able to do it for about $400 to $500. My new philosophy is" if the rotary is running funky, check the vacuum lines". Never figured out what the headlights had to do with it. HTH

dinosaur

(server error caused double post.....sorry)

FDjunkie

Electrical load will cause the IAC to feed in more air as it attempts to maintain idle speed. Headlights and A/C (plus a few others) are monitored by this system. Not sure how or if this would contribute to the problem you're experincing, though.

Gremlin1802

Thanks guys, I'm gonna keep fooling with it this week.

1QWIK7

iTrader: (33)

did you find out the problem??

i recently am experiencing this problem..i noticed tonight as i was coming home from work since its getting to that time where its starting to get dark earlier and earlier..

anyway, i noticed when i turn on my headlights, the car will still idle fine, but then as i drive..1st gear, shift to 2nd..about 2000-3000rpm in 2nd, the car started to jerk..i put it back to neutral and coasted..brought it to 3rd and same thing..i turned off the headlights and then the car drove fine..

mind you i had a slight problem 2 weeks ago but it was raining and i was blaming the rain, that night i had the headlights on and experienced the same problem..and i had to tow the car home..

so now i know its the headlights..

any solution besides a complete vacuum hose replacement??

mad_7tist

alt and battery check out?

jpandes

Could be a poor grounding points. I had high rpm hesitation before along with the radio and dash lights going out when I stepped on the brakes?!@#

I think the HD Grounding straps may have helpped.

1QWIK7

iTrader: (33)

yes, 12.6 to the battery when off and 14.4-14.5 to the battery when the car is running..

ill try and check for grounds cause i noticed even with my headlights off, my odometer dims a bit when i hit the brake..maybe its related??

but its def not a tps or an idle speed control problem right???

thanks