rdbaron9

I have a '99 with about 135k miles. About a month ago I started noticing a hesitation/misfire while accelerating. It feels like a cylinder drops out and the acceleration noticably slows down but the RPM's don't increase rapidly like a clutch slippage. Some days it is really bad even starting out with low RPM's in 1st gear or around town in 2nd and 3rd. I'm always able to get it to happen when accelerating hard going down an highway onramp after about 3,000 RPM's it starts missing and if I continue to attempt to accelerate hard the CEL starts to flash a few times and then goes out.
Overtime the CEL finally came on and stayed on. It was cylinder 5 misfire, I replaced the coil pack on 5 and it didn't help anything. 2 days later I got 2 new codes, multiple cylinder misfire and ignition signal fault. Couple days later the CEL went back out. CEL on or off it still will misfire when accelerating hard. For about a year now there is a little stutter while at idle every 8 seconds or so, but again that problem isn't always there.

Anyone have any ideas of what I could check?

kzoosho

iTrader: (16)

Knock sensor could be the cause of it. The flashing of the ses is a multiple missfire code. I would pull codes on you are and see what you come up with and then you can go from there.And you are a 99 i see . Your coil packs are on there last leg man.

vqmaxman

The misfiring and the drop to your RPM'S every 8 seconds as you said that's definetly the multiple misfiring taking place. Check the codes than get back and let us know what happend. Good luck. P.S.When your mentioning the ignition signal fault are having any starting issues?

rdbaron9

I pulled the codes manually by counting the CEL flashes about a week ago and it gave me the Multiple cylinder misfire and Ignition Signal Fault. I'm planning on looking at it again tomorrow and see if it is the same.

99% of the time it starts as soon as I hit the key, but maybe once a month I'll turn the key and it will make that terrible sound as if the car was already on but it wasn't. I'll let go immediately when this happens wait a second or two and then turn it again and it pops right off.

I haven't ruled out the coil packs but I thought it was strange that after replacing the one it didn't change anything, not even a little better. I was also thinking it would do it all the time if it were the coil packs.

Maybe it is just a coincidence but it seems if I wash my car or if it is really wet outside it makes the hesitation much worse. Although I brought it to a Car-X when it was raining out and they couldn't find anything wrong with it, and couldn't create the problem on a test drive..... although that is Car-X.

maxpeed96plat.

iTrader: (3)

Check the condition of your sparkplugs and gap to .042, regardless of what the parts shop gives you allways check your gap if you get new ones.

Digitized

iTrader: (9)

just out of curiosity, when was the last time your fuel filter got replaced?

this happened in my 92 sentra and after changing the fuel filter. car was running great!

tarun900

Could this be a throttle body issue? My dad's Volvo had hesitation while acceleration and it needed a new throttle body.

gsleve

Just as a suggestion you may want to clean the throttle body out and also clean the MAF sensor as well, take a look at replacing the fuel filter and the pcv valve. Take a look at whether the spark plugs are discolored or black coating is present more specifically look at the number 5 spark plug

rdbaron9

Alright, I replaced the spark plugs with platinum NGK plugs about 30k miles ago and gapped them myself. When I swapped out the #5 coil pack I also checked the plug which looked a light gray/white color which is good. I also checked a few others which looked the same. The fuel filter was changed last october about 4,000 mi ago. My intentions now are going to be clean the throttle body and replace the pcv.

ROCKART

iTrader: (23)

you dont need to/shouldnt gap platinum NGk plugs. they should come pregapped.

sodie14

pregapped or not....never hurts to check.