Help! I'm Misfiring!
 

Ok, I just bought this 1990 Maxima SE 5-spd less than 2 weeks ago from some college kid for $1200. It was running perfectly smooth and powerful. I work at Grease Monkey so I changed the oil(Mobil 1), tranny fluid, air filter, fuel filter, spark plugs, and put some BG 44k in it. Just this morning, I started it up and it idled like crap. It felt like it was misfiring and I lost a good portion of my power. It had a good deal of vibration ant about 1500rpm and 2500rpm. I stopped by AutoZone on the way home and replaced the distibutor cap and rotor. Now it vibrates from idle all the way to 4k rpm. So what do you all think? Timing? How do I adjust it without a timing light? Injectors? Fuel Pump? I believe the o2 sensor and the MAF are fine. help! I hate driving a 4-cylinder maxima!

what are you complaining about, I drove a 3 cylinder maxima!

BTW which plugs did you put in?
I'll bet Bosch, now go put in some NGKs. if the problem persists then :
Find out which cylinder(s) is/are dead and replace their injectors.
and don't buy rebuilt injectors, you WILL regret it.

Also, I'm not sure if Colorado has it, but SD does. The ethanol additive they put in the mid-grade. That stuff will eat up maxima injectors. I had to learn the hard way.

alright, I found out it's cylinder #5, and NO I didn't put Bosch spark plugs in it. I looked for NGKs but the closest parts store was out, so I got Denso's. Anyway, it wasn't the plugs. So you guys are pretty sure that I just need to replace the injector on cylinder #5? How hard would that be to install myself with a Chilton or Haynes. Cause the closest shop around here(Goodyear) said it could be between $200-300 to replace it.

Oh yeah, and we do get that methanol crap in CO, but it's in all grades.

there's a write up in the stickies on how to replace the injector I'm pretty sure

Yep, my idle is smoother with 91 vs. 92 (10% ethanol blend, cheaper than 91, IMHO not worth it)