Hello, Blazer gurus! Here's my problem, I have an 01 Blazer LT, 4.3 Vortec, W code, and something weird happened yesterday. I filled it up, sprayed it off at a car wash, and not long after that, it started a low idle, low oil pressure problem at low speed, that caused it to die a couple times. Thinking I had got something wet, I went WOT and didn't have an issue for that trip. Went out an hour or so later, started fine, drove fine for about 10-15 min...same thing. Tried WOT again, and it was "surging", slowed to make a turn, and it died. It sat for 5 min, started fine, drove fine for a little bit, but died as I pulled into my parking spot. Today, I drove it and had no issues. I tried WOT and heavy braking to recreate the problem, but it was fine. The only code it threw was an EVAP Code. Acceleration was fine all but once, the problem was when I slowed down, which seems to eliminate fuel pressure problems, as I would think it'd happen during acceleration too. Should I look at EGR valve, MAF sensor, something else? It does need an oil change. I'm worried about the "itsy bitsy spider" that live in the Vortec engines. I'm just confused about what to look for. Any ideas would be greatly appreciated!!!

 

It sounds like you may have gotten a connector or a sensor wet at the car wash. Try a basic solution and put an incandescent mech. light under the hood for overnight. This is to dry out the connections and other parts sensitive to moisture. Be sure to use a mech light with a wire guard on it and place it away from direct contact with hoses, plastic, etc.
Another cause of bogging on deceleration and hesitation on acceleration is a sticking throttle body plate. Clean it with a shop rag and a non abrasive cleaner like 3M intake manifold cleaner. Allow to dry thoroughly before starting.

 

Thanks for the reply. I know the throttle plate is working properly because I just cleaned it not too long ago, but I'll go over it again. Since there were no problems the following day, I was leaning towards your "something got wet" idea. I live in an apartment complex so I wasn't able to put the light on it. (Though I will have to remember that idea). I appreciate the comment!!

 

try adding some HEET to the tank possibly some water was in the fuel.

 

That was actually one of the first things I tried! Great minds think alike!!

 

Does the problem still remain or has it cleared itself up?

 

For the most part, it's cleared up. But something else is going on, I just have to pinpoint it. I noticed a constant whine that didn't change with engine speed, and some misfiring. Tracked it down to the fuel tank area. Took the gas cap off and it had a large amount of pressure. I know it's an EVAP issue, because filling the tank gives me fits. After I took the cap off, the whine went away and the engine seemed to clear up. So...I just have to figure out where to look now. Blazers are great vehicles, just so dang temperamental!

 

The fuel tank should not have pressure; so there is indeed and EVAP problem that you need to trace down. Could be as easy as the EVAP solenoid connector fell off or of course something has failed.

 

I know. It's just a matter of getting motivated enough to get under there and checking everything out. I hope it's something simple. I know the canister had issues before I got it, so maybe it'll be the same, quick fix.

 

My apologies for bumping this up, but after four trouble free tanks of gas, the sputtering and whine came back, until it sat overnight. The whine stayed, so I attempted to just drive with a loosened gas cap, but now it seems like the tank is creating a vacuum because my cap was being pulled tight. My new questions are, could something be getting filled with gas that would cause the sputtering, maybe causing a vapor lock situation? What would cause a vacuum in the tank? I did notice that during its sputtering episode, it smelled like the cat was getting hot for a short time, but that's the only time. When I tried to fill it the other day, the pump would kick off every 30 40 cents. But, after taking the cap off completely, I've noticed no performance problems. I'm dumbfounded...