Ok,
A few months back I replaced my lower intake manifold gasket and everything was seeming to run fine. Over the last week or so I have been having theses issues:
1: When I first start the car and I back out, sometimes it will stall out. But pretty much every time my rpms will dip really low when I let off the gas pedal. If I shift it into drive right away they will jump right back up like nothing was wrong.

2: When ever I am going 35+ and I lightly step on the gas pedal my RPM's will climb like normal for a second but then drop down to where they were idling until I Get the gas pedal to about 1/3-1/2 the way in. Then from there it runs like normal.

3:Occasionally, and by that I mean it will do it sometimes when I am stopped at a stop sign/light and the next it wont. I will be stopped and if my windows are down I can hear a clicking sound and when it clicks my rpms dip by about 50. It isnt drastic, it has never even come close to causing me to stall, but I also know it isnt normal.
EDIT Ok, so this morning I was just letting it run for a bit to see if I could get it to make the clicking sound and after 5-10 minutes it started to do it. From what I could tell it was coming from the driver side under neither the air intake tube. It was pretty random so it was hard to actually pin point it.

I have never had the clicking sound happen in a situation where I can actually pop the hood and try to figure out where the hell it is coming from.

OH, one last thing, when I changed my lower intake gasket I found out about a month later that my heater/air vents will not change off of the main dash vents.

 

I'd check vacuum lines. What vehicle is it? People need to know the particulars, Make, Model, Year, Mileage, 4x4, 2wd....

 

Oops, yeah, I bet that bit of info helps, sorry. It is a 1999 chevy blazer, 4x4, around 117k miles.

 

Rottidog is on it regarding vacuum issues!But there may be not only that thing going on. These gauge clusters are NOT reliable and are suseptible to problems. You may also have trans solnoid issues as well as other components contributing: IAC,MAP etc But The unit should be throwing codes in that case,CEL on? The clicking is a physical issue it seems to me,unless you missed something upon re-installing the intake:correct torque etc...or else you may have a valve train issue-Was it there before? If not,recheck your work! 117K is too young for these to go south IMO-Gotta be something simple! step66

 

Which happens to be right next to the Fuse/relay block, right?

Pull the AC Compressor fuse and see if that stops it.

 

Step66: I have not had a code since I replaced my LIM gasket(which I was getting a P0300). Before I replaced that the clicking sound was there and doing the exact same thing. When I pulled my intake manifold I found that actually the gaskets were perfectly fine, it was the seal that runs along the block that had broken down.

Pettyfog: Ok, I will check that today, curious, what makes you say the ac compressor? Which, speaking of the compress. When ever my heat/air is on, when the pully engages/disengages on the compressor, it makes a loud clunking sound, is that normal or is my compressor going out too?

 

Nothing specific, esp if the comp is cycling normally. On the clunk, look close and listen.. if it directly in sync with clutch engage, probably worn clutch and clutch pulley gap more than .030".

You really cant tell how worn it is until you take it off but by the time the pulley bearing is worn out the clutch is too. Found that out the hard way.

 

Ok, so I pulled the AC fuse and the clicking continued. I think my best start is to start looking for any sort of vacuum leak. All of these problems(except for the heater vent issue) was all there before I fixed my LIM leak. When I Was looking this morning, I am 99% positive that the clicking sound is coming from the top of my engine around the driver side. If I moved over to the passenger side and got close to my engine it was a lot more feint.

The big thing that I cant seem to figure out is what would be causing my acceleration problem. When ever I am below 40-45 mph I have zero problems accelerating at any pace. But once I go over that point and I try to just give it enough to maintain speed I get a slight surge in RPM's but then it dips back down to where it was idling.

 

I am not sure I understand what you are saying. Are you saying it wont go over 45 mph?

 

No, it will. Ok, best example I can think of. You are cruising along at 50 mph, you hit a small incline. So you give it just a little gas to maintain speed up the hill. When I go to do that, my rpms will rev like it should. But then, with the pedal still pressed in, my rpms will dip back to where they were when I was coasting. Once the gas pedal is pressed about 1/3-1/2 in it will rev up like 600 rpms and stay steady like it should have been the whole time.