: 2003 dhs p0300

01-03-09, 07:14 PM
2003 dhs 75000 mi. was running fine and all of a sudden started to stumble. rough and low idle and stalled. pulled over got out and had a strong smell of rotten eggs. started car back up ran fine. couple hrs later went to pick wife up from work started fine about 2 miles out did the same. shut off, let sit a minute. started and ran fine again. went to Sunoco filled up with premium gas drove home told wife to take the bus. (didn't go over well). went to store later and happened again. seems to be doing this when on the accelerator. limped a block to my house, this time service engine light came on as i was pulling into garage. was flashing. stunk up garage like rotten eggs. this time got a code of p0300. misfire. only code in system. light did not come on previous "attacks", just ran like crap and smelled worse. go out there now. starts fine. scared to go anywhere though as i dont want to do any damage to anything. any ideas would be greatly appreciated. thanks

01-03-09, 07:40 PM
Check the FPR for a leak. Also check the plenum for a leak. The plenum is the rubber coupler between the TB and the manifold. They tend to split on the bottom so it is not easily seen. Spray it with Brakleen and listen for an RPM increase.

01-03-09, 08:07 PM
Thanks for your time with this. will go check FPR out and post what i find. again thanks

01-03-09, 10:35 PM
The rotten egg smell is quite possibly your battery.

01-04-09, 11:26 AM
QUOTE (BodybyFisher @ Jan 3 2009, 08:30 PM) *
I agree with Jim, its a cylinder misfiring for some reason. The more I think about it the FPR would not set a P0300 code, the rotten egg smell made me think in that direction.

Check plugs and wires as Jim noted. A vacuum leak can also cause P0300 but that is unlikely since no work was done to engine and you are not getting a lean code.

Thanks for the responses

Could not look at anything last night, here however i did start it up this morning was running fine and problem did not occur until it reached operating temperature as i was pulling into garage. code popped p0300 again.. misfiring pretty heavily. Only other codes were irc u1016 history and pdm u1713.

I have autozone 2 blocks away so i got a obd II AUOTO SCANNER made by actron, model cp9176l on loan. could this scanner help in any way? figured could not hurt. just waiting for it to cool down so i can go try a few things.

Car is still under warranty from when bought. Only the basic lemon law 60 days. i believe the ignition system is covered as is under 80000 miles.
Should i just leave it and let them worry about it? also to far to drive it in this condition unless i keep stopping and letting cool down. about 20 miles.

01-04-09, 04:45 PM
If it's under warranty, let them worry about it. Could be a plug, boot or ignition cassette.

Your car has on board diagnostics and will do a much better job than Autzone or most after market scanners.

01-04-09, 06:09 PM
Watch the tach at idle. See if it moves around a bit. stab it once and see if it comes right back to idle and doesn't vary. If it does vary it is probable the Boot. My 2002 DHS had that problem at 60,000 and it comes and goes as the rubber gets hot and cold and flexes. Depends on the crack in the boot. Always seems to be on the bottom where you can't see it. :rant2: Like Ranger said, let the dealer fix it if under warranty. The dealer tech had to remove the boot to find the split on mine but the tech II tool showed a lean condition come and go.

01-05-09, 12:44 PM
could this have been just possibly bad gas??? maybe water in gas?? as soon as problem started went and put sunoco 93 in. very short distance from my house. only posted code twice since problem began. lucky if i drove it a mile total. ran it in garage until operating temp reached. it happened again. but next time i went out and ran again , all is well . took for a ride no problems. have not done expressway yet but will this afternoon. good luck to me. have to go to work to pay bills you know.

01-05-09, 06:16 PM
Anything is possible, but I'd doubt the gas.

01-07-09, 04:51 PM
all figured out now. or at least we hope. rear valve cover leaking filled spark plug wells causing the misfire. so new gaskets and a tune up and what the heck throw in a fuel filter. will get back on friday. cant wait to have it back as everything else i drive in feels like a go cart. dealer covering most. so thats cool. hopefully no more problems for a while.