OK I'll give a little recap. I've recently had an issue with a slight hesitation from 45mph and up. Once it's warm (not when it's cold) I get a hesitation at differing degrees of buck. Sometimes it's a slight hesitation, sometimes it bucks and chucks all over. Well when it does this it gives me a code no the obdII reader of map or barometric pressure sensor low voltage input. I believe this is due to the vacuum dropping off throwing off the map (since the map has been replaced. Now I've found that if I unplug the evap purge solenoid the truck will run fine but will give the P1442 evap circuit open code. But the truck will run PERFECT.

So today I went to pick a part. (first excuse my rant) I get there. I find 5 engines like mine (95 model with obdII) but 1, and I mean only 1 had the solenoid. And I don't mean they were taken off, I mean the damn engines didn't even have one to begin with. I even found a 95 that had just been brought in and the entire upper intake was untouched. Sure enough, no solenoid. But I got the 1 that was found. So at first it didn't change the engine performance. Still a slight buck at 45mph and up. Well only when letting off the gas a little. Not while speeding up. But I brought it home, pulled the fuses for 5 minutes and let the computer completely reset and took it for a test drive. Seemed to go fine. Performance was good. And if there was 1 hesitation I can't be sure as it could have been a bump in the road. That's how slight it was.

So first my question on performance. If, say I unplug that purge solenoid, and the computer gives the SES light and the purge circuit code, does that put the computer into a default mode? I ask this because my grand am had this happen when the egr went bad (a common issue). If it threw a code it would put the computer into a default mode where it would make the engine run rich. Reason I ask is, when the truck was bucking it seems like there is something throttling the gas, like it's running really lean. That's why I thought I had fuel issues. But it's not, it's just something throttling the gas. This is quite evident since just unplugging the purge solenoid will cause the truck to run perfect. And before asking, no it does not have a vacuum leak. I've had a vacuum guage plugged in and it has a steady 19.5psi.

Now my question on the purge canister in particular. Now there are 3 lines that plug into it. There is one larger one on the bottom that is labled AIR on the canister. And there are two that are plugged into a plastic block above it. And on that block is labeled PURGE. Now if I unplug the bottom air line nothing important. Doesn't seem to affect anything. If I unplug the top hose on the purge block, nothing. Now when ever I unplug the middle hose, which is the bottom one on the purge block, I get a little bit of fuel flowing out. It's not a lot. Maybe enough to fill a Pepsi screw cap. Is this normal? Oh and if I uplug any of those hoses it will eventually throw a code, though I do not know what as i've not had the scanner with when I've attempted this. So just want to know about that gas coming from the lower purge line and any info on cleaning the canister if needed.

 

There should not be fuel in the evap canister. Sounds like yours has become saturated and is in need of being replaced.

 

Ya know this kind of is starting to make sense. See if this sounds right. If the canister WAS getting saturated to the point where fuel was collecting in the bottom of my canister......OK the line marked AIR sits on the bottom right (looking from back to front) of the canister, if you take a left the fuel plugs the hole on the right, if you jackrabbit start, it plugs the hole as it is on the back of the canister. Hell this could have been the whole cause for the stalls (though I seemed to have fixed that now.

But my remaining question is this, where to those two hoses on the purge go to specifically? See the top one is dry but the bottom one still seems to have a trickle of fuel come out of it. I'm searching everywhere to get this info. I need to know if this is supposed to happen or if not how to stop it. I am assuming the AIR hose goes to the purge solenoid on the engine. I know ONE of the purge lines goes to the vent on the front of the tank. Just which one? Kinda hard to chase them down as the metal lines are hidden on top of the frame.

 

OK I actually got under and dropped my canister. It appears to be OK. I was able to blow through all three holes. It was not the problem. The deal with the fuel trickle seems to be tapering off. There only seemed to be a few drops today when I disconnected the lines. So I found out where the lines go. The big one that is labeled Air goes up to the fill tube. The lower of the two on the block, the block is labeled TANK. This is the one with the fuel trickel. And the top one which is lableled PURGE goes up to the engine and the purge solenoid.

So far so good. I also found that my pcv valve was cracked and falling apart. Since replacing THAT also the truck is running good, no bucking and chucking and SO FAR isn't throwing a code. So I'm going to let it go this week and see if there are any changes. If not I'll post on here. Basically the repairs consisted of:

replacing the hose clamp on the fuel pump line in the tank.
reconnecting the vent hose on the vent on the front of the tank (which has become disconnected)
replacing the purge solenoid (The most important one)
and replacing the pcv rubber elbow.

So let y'all know how it goes this week.

 

OK here's the update as promised. I finally have the truck running perfectly. It drives like a new truck now. It hasn't run this smooth since I bought it. I always had one little hickup here and there. Since last jan I had the issue with it stalling when it would turn left or jackrabbit start. Well now it's all good. I've been driving it all week. Even the wife drove it in heavy traffic across the city. Not so muhc as a hickup or hesitation and NO CODES! So this can be a heads up to others that might have similar issues. it basically came down to the purge solenoid.

 

Good news! Thanks for the follow up!