Hey, I'm new here, hopefully you can help me out.

I have a 1992 240SX with 138k on it. I am bothered by the poor accelerationm, especially in first gear. In the past it used to grab a lot better, now it feels like I have no power when accelerating. I have recently had the spark plugs and wires replaced (NGK), the fuel filter replaced, and I have a good air filter. I have read around the internet and people with similar issues with acceleration/power have found the problem to be a vacuum leak somewhere. However I don't know the slightest bit about how any of that works or where to even look. Can someone please help me out?

 

tighten up your throttle cable

 

it's probably not your throttle cable, but do check it out to be sure.
If you have a vacuum leak, you are losing power. However this is not easy to fix.
I have a couple suggestions,
1. Remove the AIV, because that helped me out with acceleration, and if your AIV is kicking the wrong way it could be causing your problem.
2. Do you use fuel injector cleaner? because you should be.
3. Have you heard of seafoam? It actually helped me out a lot, cleaned out a bunch of junk from my s13. 4.
4. Clean your throttle body, take out the intake and spray in some carb cleaner and really clean it out, it will help
5. Clean your MAFS, it could be reporting aincoming air incorrectly, which would cause bad performance and bad gas mileage
6. Your cat could be clogged as well.

That should be a good start

Dr.

 

all that the Dr said plus do full throttle acceleration at ~ 50mph in fifth gear to see whether it is the engine is unresponsive or the clutch is slipping. Sometimes it's harder to notice slippage in lower gears.

 

and..... check to see if you have any loose vacuum hoses floating around. they are extremely small, so just look, I wouldnt touch any, cause your car is old and if you pull one off you may never get it back on without paying someone. Just check obvious things, if you have loose hoses, get an owner's manual and check what it is thats loos, or missing!
Russ

 

definately remove/repair the AIV..it helped me somewhat on acceleration.

 

wouldn't a burnout in 1st be an easier guage to see if the clutch is slipping? Provided of course, you find a place to do a burnout without getting ole' smokey to bother you

 

Okay, thanks for all the responses. Whenever I get a free weekend I'll check out those suggestions.

I did fail to mention something that might be insightful: My car seems to have gotten louder over the past year (while I've noticed this lack of power). When applying the gas pedal it just sounds loud, kinda like the high speed turbulent airflow noise you'd hear from a broken fan blade on something. Just FYI, I've had the fan clutch replaced within the year. I don't know if this noise means anything or not, but it does coincide with the onset of my poor acceleration problem.

 

Exhaust leak maybe?

 

yeah, thats what I was thinking. Is it the sound of loud rushing air, or something else? I think rainy is right.
Check all of that out and let us know.

Dr.

 

Yeah, I have gotten a ticket for "Illegal Start from a stopped position" before. Freaking dyke cop wanted to show who was boss.

 

Apparently she did

I wonder if "Illegal Start..." is the same $$ as "Exhibition of Speed" because I knew someone who got caught doing a burnout and they tagged him with that instead