Rep Power: 266

So this is really pissing me off because my car normally gets 34-40 mpg, but now I'm doing 30-35. The engine sounds great but accelerates slow and revs really high for the speed I'm getting. It just feels like ONE thing that's messing everything up.

What I already tried, all OEM parts:
Adjusted ignition timing.
New fuel filter, fuel pressure regulator. (a waste of money as these are magnet-based and don't really fail)
NGK platinum plugs
Oil change, castrol 5w-30
Alternator charged battery to 13.6v, so it's okay.
Plug wires. Tested for resistance, passed tests.
air filter, new.

Suspect:
Rotor, distributor cap. How do I know if they are bad?
Ignition coil? Checked resistance, passed.
Weak fuel pump?
Dirty fuel system?
Throttle position sensor? (Tested, goes from .47-5.00 volts)
Is there a screen in the gas tank that could be clogged?

 
Rep Power: 352

change ur fuel filter.
seafoam ur car
get some FP60 so it'll clean ur injectors..

 
Rep Power: 512

toss some STP complete fuel cleaner in your tank.. $5 at Target, and it really couldn't hurt..

 
Rep Power: 812

use auto-rx.com in the oil for 5k miles. maybe the motor is just getting old and needs a good cleaning. cap and rotor are really cheap and easy to replace, might as well do it if you havent. black burns inside can indicate if they are too old. after the auto-rx, start using lubecontrol.com products in oil and gas. if youre already using em, the lc20 is not a powerful cleaner, it only keeps a healthy engine in good shape. if you have a neglected motor, try the auto-rx. its working miracles in our 92 accord already.

 
Rep Power: 266

Does anyone know if fp60 goes bad? Because I have some that's 6 years old and been exposed to the sun, and now it's clear instead of hazy pink.

Any way, I picked up some STP since it was cheap. Will let you know...

 
Rep Power: 266

Yeah it's a good idea to try the auto-rx stuff, but right now I want to see if the fuel system is the problem.

 
Rep Power: 812

the fp-60 had some weird issues with stuff settling out of solution so you have to really shake it up. im not sure on the shelf life but i heard a couple yrs from somewhere. the fp-plus is completely homogeneous liquid and there is nothing to shake. so at least they improved that part. i would just toss the old stuff and go with fp-plus.

 
Rep Power: 266

Thanks for the info gearbox. I'm wondering about my distributor cap and rotor. Bought them about 2 years ago, made in japan from Napa auto parts. The electrodes on the cap are aluminum or whatever, but they keep getting this white char on the insides where the current hits, and I have to scrape it off with a small flathead. Is that normal? I can post a pic if you want but I'm so lazy now.

 
Rep Power: 0

Any possibility the breaks are riding?

 
Rep Power: 812

just clean up the distributor parts if they are dirty, but you should not be getting that much buildup. a little black soot is normal.

 
Rep Power: 209

I had the same symptoms when my brakes were messed up but my MPG dropped down to the mid 20's so i don't think it's the brakes.

side note: I just got the best MPG I've ever gotten! 41.85 MPG!!!!

 
Rep Power: 266

Good call but I did a brake job recently, even took apart the calipers. There was nothing wrong before or after.

Turns out it was a dirty fuel delivery system. I put some black-bottle STP in the tank while it was half full, and 3 days later the engine is running like a champ. I'm going to run one more bottle after this one too. So thanks to all of you who said it was a dirty fuel system. I suspected the same thing but I ran the expired FP60 through there thinking it was doing it's job, but in fact it was making it worse! I wish I had run the STP before shelling out $52 for a new fuel pressure regulator. Oh well.

 
Rep Power: 812

i was always iffy about that fp60 with the stuff settling out. i never had an issue but i finished that bottle in a year and switched to the new stuff. been using that ever since and seems like it will keep for much longer.

 
Rep Power: 266

The original fp60 definitely works. I used almost a galon of it in my car and gave some to a friend. We both effectively cleaned our systems with it. Also, I ran it through 2 different volvo's and it cleaned their systems too.

I will definitely give the lc20 and perhaps the new fp60 a try in the future.

Oh and I wanted to ask you what your take on seafoam is. (I know auto-rx is a good choice)

 
Rep Power: 313

Glad it was an easy and cheap fix

 
Rep Power: 812

i dont like seafoam. ive heard too many bad stories about engines being ruined.