MISFIRE 1 2 3 4 2001 CNG

[jrp544jim]

hey all, trying to help my broinlaw with his civic dx. 2001 CNG model. told me he was having a bit of engine sputter on cold start, then would clear up. alos has multiple misfire codes. about 130k on car , no previous records as bought from PGE power company in cali. has had car about 1 yr. had him change plugs and put in new ect. that was last week. he called last nite, says barely made it home, engine badly misfiring, no power, MIL light back on. now up to this point he says the car was starting better and his fuel mileage came back,but then yesterday had the big probs on the way home, ran ok in am towork. reading and searching it seems these cars are very plug sensitive. i believe car had NGK but he put in AUTOLITE. could it be as simple as changing back to NGK's? had him read the codes and he sent the freezeframe info posted. codes p0301 /02/03/04 and mutiple misfire with flashing ck light. so wondering on course of action for this? told him to change plugs &let me know. one prob, he is 200 miles from me so trying to diagnose over the phone. any and all info would be greatly appreciated. thanks, jp
Dtcfrzf reading p0301
Fuelsys1 reading 0L
Fuelsys2 reading is n/a
Load-pct ......38.4
Etc(f) reading is 59
Shrtft1(%) reading is 0.8
Longft1(%) reading is 0.0
Frp(psi) ..... Is 30.5
Map(inhg) ...... 11.5
Rpm(/min)......1474
Vss(mph)......0
Iat(f)......73
Tp(%)......9.8

 

[Tony88]

JP,

I have been having similar issues. I changed all my coils which helped my misfiring and i used seafoam in my gas tank with 93 octane to try to clear out anything in the injectors etc. It helped temporarily until that tank was out. I have narrowed my issue down but have not been able to fix it due to it being my daily.

If all the cylinders are misfiring i doubt it is the coils. Start the car and then try disconnecting the EGR as shown. Then see if if it idles better and try to drive it around the block. I found that i had no issues at all and therefore need to get into the intake housing to clear out the carbon build up from what a mechanic told me (my uncle). I will try to send pictures when i get to this possibly this weekend if i can find time for it to be garaged.

If that does not help i would def go to NGK's regardless. That is all i have used in mine.

Give that a shot and see what happens. Good Luck!!

-Tony

 

[lethal6]

Get that aftermarket crap out of there asap. These don't run well with anything outside of the normal NGK.

 

[XpL0d3r]

Also, if he's getting a flashing CEL, do NOT drive the car. Flashing basically means that if driven, it can cause further issues.

 

[jrp544jim]

thank you, tony88, lethal6 and explod3r, i have passed all info on to b-inlaw, supposed to hear from him this weekend, will advise when more info arrives jp

 

[lethal6]

Also, if he's getting a flashing CEL, do NOT drive the car. Flashing basically means that if driven, it can cause further issues.

Didn't see that it was a constant flashing CEL. Yeah, that is bad news. It's really pissed off now for some reason. Might be deeper than just the aftermarket plugs or the plugs caused a bad misfire and damaged more stuff.