wife drove it once, now my 03 Tahoe has CEL

[Mike1980B]

bought my truck a week ago. no problems running fine all week. my wife drove it last night on a 40 mile round trip and came home with the CEL on. so I borrowed my neighbors OBD scanner and read the codes. I got 3 as follows:

P0300 Random/Multiple Cylinder Misfire Detected

P0332 Knock Sensor 2 circuit low input (bank 2)- code registered twice

I cleared the codes, light went out. hasn't come back on yet (knock on wood)

A little history on the truck. 2003 Tahoe 4x4 5.3L former police unit. currently has 186K miles. unknown as to when last service was done, but all fluids are fresh and clean.

I was thinking it just may need a tuneup. its been sitting on the dealer lot for a few months. now that its got fresh gas in it and driving around, it may be time for a fresh set of plugs and wires. If anyone has any other insight on where I should start please let me know. Thanks

 

[Nappers]

Plugs/wires, make sure they are the iridium plugs. I put a can of Techron in my tank time to time to clean 'er up. I also seafoam once a year through the brake booster vacuum line and tear apart intake and clean MAF, intake.

Don't blame the wifey! LOL! (not that I wouldn't!) "What did you do????"

I would start there, or at least pull a plug and see how it looks. knock sensor may be due to bad gas, multiple cylinder misfire, same. Run good gas, I dump a can of seafoam in tank once in a while too. Don't think it don't hurt..... almost 175,000 miles on the clock, only changed 2nd air injection valves, right rear window regulator and a deer insulted front end and replaced the tranny at 149,*** miles in a gravel driveway (that was fun).

 

[Mike1980B]

Thanks Nappers. Any recommendations on Plug brand? Im thinking NGK or Denso. Always heard good thinks about them. Or performance wire recommendations? MSD or Accel ect? I hear a lot of guys on here talking about Seafoam. I personally have never used it before. But Ill give it a try. Ive always used Lucas's fuel treatment in my vehicles. As well as the oil stabilizer in the engine, transfer case, and diff's. As soon as it warms up around here Im planning on doing a FULL Synthetic overhaul on everything that takes fluid.

 

[Rivieraracing]

I like OEM plugs and wires on our truck if they are stock, my truck runs awesome and that's what I'm running with now!!
Did the truck run any different when the CEL was on?

 

[chauncey0337]

I like OEM plugs and wires on our truck if they are stock, my truck runs awesome and that's what I'm running with now!!
Did the truck run any different when the CEL was on?

^^X2. Here you go, read post #7-
http://tahoeyukonforum.com/forum/showthread.php?t=35264

 

[WildBill]

Acdelco plugs (rebranded NGK iridium), Accell wires. I would try a higher oct gas for a tank. was it cold out? the o2 sensors may be slow to warm up or maybe they are worn out.

I've never used seafoam, but I have read the posts on here about how the seafoam treatment made it run worse. I dont know about it, but I know i dont trust it. my .02c

 

[Mike1980B]

Yeah Wildbill, the night the CEL came on it was about 25 degrees. I ALWAYS LET MY TRUCK IDLE FOR 5-10 MINUTES before i drive it from cold. My wife not so much. shes impatient.

 

[FLO-LOP 805]

From what your codes say!
r/rear o2 sensor going bad (passenger side)
the engines miss code p0300 is common bad plug or wire
Stay with factory plugs and wires/they last 100000 miles!!!

 

[pstahoe]

my 2003 Tahoe 5.3L flex fuel is having similar issues. Lost RPM's and power 20 plus times over a 200 mile drive. No issues on the return drive of over 250 miles. Does it intermittanly at various speeds triggered by an attemt to accelerate. I let it idle for 25 minutes and it staring varying and died towards the end. Code says a pending p0300. Always restarts and runs strong in the interim. 105k miles.

 

[electro]

Did the KS code go away?