Im stumped...please help...

[serboliver]

Ok, I have had this particular problem for about 4 months now. And I cannot figure out what it is.

First..my car...

93' s-13, stock motor, injen CAI, 5zigen fireball exhaust, PDM dump-pipe...those are all the engine mods.

Second...the problem(s)...

Sometimes (not all the time) on rainy days, after about 10 minutes of driving, the motor will sound like its choking. A few times, it got so bad that I have had to nurse the throttle and clutch to keep the car moving so I could get home. The motor has no power when this happens, I push down the pedal, and it hesitates (kinda like the car has no gas, but it does).

Other times, after about 30-45 min on the highway, the same thing will happen, but to a lesser degree. On these occasions, usually I cannot go above 3500rpm or the motor will start to sound like its choking again (again the "out of gas" type of hesitation). This will not happen for long, sometimes it happens for about 2 or 3 minutes, and then just go away. Other times it will persist for the duration of my drive.

Needless to say, all these things make me very nervous driving the car.

Third...what i've done...

My first thought was that the CAI was getting excessively wet in the rain, and that the dust in the dirty filter was holding the water and choking the motor of air. So I thoroughly cleaned the K&N, oiled it up, and reinstalled. I also semi-sealed the area in the wheel well where the filter is located, and blocked the air inlet duct below the drivers side turn signal with a piece of clear plastic and sealed that as well. So I am sure that the filter is staying dry in normal rain conditions (except of course big puddles, but I avoid those or drive very very slow thru them).

Once I did this, I was sure it would fix the problem. Not. On my next trip to Houston, the highway hesitation happened again. When I got home to my parents house, I brainstormed again. My next guess was that the motor was not getting enough fuel...maybe a dirty fuel filter....so I replaced that. That seemed to help a little bit, and again, I was convinced that I had fixed the problem.

Low and behold, on my way home on the highway, more hesitation.

Now, none of this hesitation has actually happened in the past 2 weeks, but am I missing something? Is there something else that could be causing this to happen?

All information/help would be appreciated very much.

-Oliver

[red240ne]

Could be a few things:

Check for vacuum leaks. Check all of the vacuum hoses, make sure that your intake is all sealed up good.

Could be ignition problem. Timing is retarted, or maybe plug wires or plugs are bad.

Could also be bad o2 sensor. When's the last time you replaced it? If you do replace it, get the dealer's version of it, because it will be much more reliable.

Edit: College Stations, Texas baby!!! Gig em Aggies!! I can't wait to go to the Texas/Texas A&M game next year. It will be my first trip to College Station.

[serboliver]

I've considered those things. But its weird once I think about it....why only when it rains? And, why only when im cruising at high engine speeds on the highway?

I checked the intake for leaks and obstrucions. The o2 sensor was replaces about 20K miles ago (might be due for a replacement), the plugs were changed out about 20K miles ago as well. Plug wires...dunno, they look alright (not melting away), but they are still original stock.

And, I have no idea how to adjust timing....didn't think my car was souped up enough to mess with that stuff...heh

Oh....hopefully with Franchione A&M will be a half *** football team for once, so MAYBE we will put up a fight against Texas. But in all honesty, we will probably get slaughtered again unless Franchione pulls a miaracle.

Im still optimistic....at times

[red240ne]

Yea, I was so hyped a year and a half ago when I heard Reggie McNeal had commited to A&M. I had been following that guy, and know he will be something. If nothing else, McNeal will be their god.

Might as well just replace plug wires, although it most likely won't be the root of the problem.

The FSM gives another suggestion I didn't mention:And I quoth...1. Remove vacuum hose from Pressure Regulator, and try to drive.2. Connect vacuum hose to pressure regulator and measure fuel pressure while driving.3. Check mixture ratio feedback system.Don't know what they're telling you to do, but anyways, is your check engine light on? Run a diagnostic test if that's the case..

[JeromeS13]

Even if the light isn't one, I'd check the ECM codes.

[erich]

Is sounds like marginal plug wires or a bad distributor cap. When it gets really humid they will have a weakened resistance to arcing.

erich

[serboliver]

Is sounds like marginal plug wires or a bad distributor cap. When it gets really humid they will have a weakened resistance to arcing.

erich

aha...this sounds like it might be the problem.

all the other suggestions sound great, but this one sounds like it has the most promise because of the problem mainly occuring while its raining, or right after a rainstorm.

i could check the ecm codes, but i dont have a tester.....<sigh>....and the check engine light is not on...

thanks..

-Oliver

[JeromeS13]

You dont need a "tester" to check your codes. Goto the FAQ on http://www.240sx.org and it'll show you how.