hey guys

[garyk1970]

my wife has an 02 tahoe 5.3 4x4 ls. 92k miles
cold idle rough,cel blinks,three codes;
p0171 ;lean bank 1
p0174 ; lean bank 2
p0300 random /multible misfire detected.

anyone seen this before? im sure a silverado is very simular? im an ex- gm service tech,but drivability wasnt my job then....im electrical.

new air filter insatalled (i know it wasnt the problem,just going to do a tune up)new plugs and wires tonite,going to check the fuel filter.
done a tap on the mass air sensor and cleaned it-
any other ideas? throttle is mechanical (good ole cable, no motor)
thanks in advance,Gary.

[01SB327]

have you been able to hook it up to a scope?
check your injector pulses.
also check your o2 sensors.
if you can get your hands on a modis or something of that nature (solus)
run a full diag and monitor the truck in all operating conditions.

hope this helps a little.

[1slo4.8]

i don't know about in the GM world but i know in the Hyundai world that with our cars a bad 02 can create miss fire codes

[Ramsey]

wow im having the same issues as u ,i wonder if its the colder temps,i just posted,weird i just noticed we have same b,day and year.kinda freaky.

[01SB327]

wow im having the same issues as u ,i wonder if its the colder temps

colder temps should have nothing to do with it.

the lean condition is created with an improper fuel/air mix.

and that triggers the misfire condition.

check your cats and your o2 sensors.
the o2 play a large role in a/f ratios.
also check the coolant temp sensor.

[Ramsey]

ya but 4 me something triggerd it ,b4 the temp change i was tuned 4 no cats and no rear o2s ,and i was alittle rich if anything but then i slowly noticed the change in a/f with my temps.i could be wrong but i read a few post that said they were running lean with the colder temps.im in n.y. and its getting below freezing.im open for ideas thank you and sorry for jumping in on the post ,i just have similar circumstances.

[garyk1970]

wow im having the same issues as u ,i wonder if its the colder temps,i just posted,weird i just noticed we have same b,day and year.kinda freaky.

your b-day is aug 12th? if so, you have to be alright.....sorry just seen that i never set my b-day??is nov 30 automatic?

[garyk1970]

have you been able to hook it up to a scope?
check your injector pulses.
also check your o2 sensors.
if you can get your hands on a modis or something of that nature (solus)
run a full diag and monitor the truck in all operating conditions.

hope this helps a little.

i see what youre saying but both banks lean at the same time would most likely be a bad maf,fuel pump/filter,etc.
no scope....wish i could get my hands on a tech2.

[DamnYankee]

...might be knock sensors - I had a similar problem...

I think there's a thread on here but I'm heading out, so you might try a search.

[Ramsey]

well i guess its not so weird then ,that would have been messed up ,same problems are enough of a coincidence.o well ,i dont know if it automatically sets at that or not,good luck.