Mas00

Was driving on the highway and the RPMs revd up after around 75MPH and my check engine light started blinking. It then quickly went away after like 10-20 seconds. Then I put it on cruise control and it did it again but this time it stayed blinking my whole trip. I couldn't pull over cause I was traveling for work which was about 25 minutes.

Went back in my truck after work and the light is gone.
I've done most of the work on my truck itself ( Accept when the fuel tank/sensor was replace about 9 years ago) but nothing major. I just gave her a tune up at 170K miles, wires, plugs etc.

I've read that it could be a gasket leak, O2 sensor, timing cover, crank sensor, basically down the damn rabbit hole.

I didn't get a chance to read the error code but any suggestions on where I could start? Thanks I called about replacing the O2 sensors and it's $300, but unsure if that will solve the issue..

oldchevy

Put a scanner on it and read the codes. Why guess when you can get the answer. You can take it to one of the auto stores that reads your codes for free if you don't have a scanner.

tech2

the engine is misfiring. +1 for getting the codes read

2001 chevy silverado

#1 assuming misfire is WRONG. he never said that he/she never said "runs rough" either

ALWAYS insure battery is 100% before diagnosing / testing. a low battery causes any system to "GO WACKO". don't even start before checking the battery. not anytime and every time

NEVER REPLACE A COMPONENT WITHOUT TESTING IT. IT ALWAYS COSTS MORE TIME AND MORE MONEY IN THE END. worst mistake shady tree mechanics make. There's another down side: if you never confirm what isn't working you'll never know if the new part isn't working either really: that's so backwards!!!

the exception is the O2 sensor. you can test it but not fully test it without a sensitive scope you don't have. it could be expensive ($300 is outrageous shop elsewhere - that's your problem)

we all know you need the code. but if it says O2 for goodness sake check the wiring and the resistor values first.

yes it's possible that kind of symptom can be cause by O2 - but, say EGR, might cause issues and throw O2+EGR

Mas00

Been driving my truck normally not pushing it too hard on purpose to get the CEL back on. Just driving normally like i was before. The light has yet to come back on so I don't know anything until I can get the code.

tech2

I am not assuming anything about a misfire....he said the mil was flashing. it only flashes when the engine is misfiring. this signifies potential cat damage and it needs to be addressed immediately. You need to do some googling before giving anyone car advice.

Mas00

Ive done TONS of goggling which is why I'm here! Nothing specific has come up and the engine light still hasn't came back on flashing. I'm asking for advice not giving it lol

chem_man

Mas00 - the first thing you need to do is to get a code reader and hook it up and see if there are any current, pending or historical codes. This is a must do.

After you have obtained the OBDII codes, come back reporting the codes you obtained,and if they were current, pending or historical. Then we can proceed with assisting you.

tech2

my quote was directed at 2001 chevy .

codes should be stored unless you disconnected the battery or the problem did not reoccur in 40 key cycles. next time it happens get the codes read and post them here. that is the diagnostic starting point. if no codes are setting, mil not flashing and you have no drivability problems...you are fine.

Mas00

So I got the codes ran today and the C0226 and C0222 code came up which is the front L/R is missing a speed sensor?

Also I got P0101/2 Mass flow air sensor
P0300 and P0351 ignition coil control 1

I got a flat repaired at Costco about 3 weeks ago and I called them about it but they just said not responsible because it's located on the hub?

How do I got about repairing these issues. Do I need to get new speed sensors for both? It's been a while since I've changed my brakes but I doubt that could be the issue.

Never heard of mass air flow or is repairing a coil difficult?