Odd hesitation on acceleration

[88olds32]

I replaced the fuel filter and EGR valve with OEM parts and am now noticing it bogs or hesitates when I floor it. The bogging/hesitation only happens when I'm traveling at 40ish mph. Not sure if this will help diagnose the problem, but, I also noticed that when the engine idles and is warm, the rpm needle is slightly over the 1000rpm line. I can also hear a whistling of some sort, which I'm thinking might be a vacuum leak.

Any thoughts on what the cause might be?

This is on a 88 Olds with the stock 307.

 

[88hurstolds]

Vacuum leak and/or accelerator pump is worn.

 

[pow3rwagon]

I don't think it is the accelerator pump if this is happening at cruising speeds. It sounds like a vaccum leak to me. You can check your accelerator pump and I use starting fluid to help find vaccum leaks

 

[88olds32]

Yea, I have a feeling it's a vacuum leak. I can hear it, just can't seem to find it through all of the vacuum hoses. I might end up replacing them all.

 

[88hurstolds]

I don't think it is the accelerator pump if this is happening at cruising speeds. It sounds like a vaccum leak to me. You can check your accelerator pump and I use starting fluid to help find vaccum leaks

I replaced the fuel filter and EGR valve with OEM parts and am now noticing it bogs or hesitates when I floor it.

Cruising speeds or not the engine is starving for fuel upon acceleration.

 

[pow3rwagon]

All I said is that I didn't think that the accerator pump was the issue since he stated that it only happened when he was going 40ish. Accelerator pump would happen at all times. He could be starving for fuel or possible air or spark as well. I think he should check his pump as I said before. I'm betting on a vaccum leak as he said he can hear a vaccum leak. The other issue I'd it may be the vaccum advance on his distributer. I was just giving him my opinion sorry if it conflicted with yours. if it's the accerator pump congrats to you you get a point.

 

[88olds32]

Update: So I removed the air cleaner, and looked through all the many vacuum lines and hoses. I eventually noticed one of them was dangling. One of the below pictures shows the line. It has an elbow type connector and is located between the carburetor and the distributor cap on the driver's side. I dug some more, and noticed there was a nipple somewhat near, so I connected them. Can anyone tell what this vacuum line is and if I connected it to its proper location?

After connecting it, I took her out for a spin. It still did the same thing though. Previously, when I felt the engine was going to bog/hesitate/die, I would remove my foot from the pedal, and the car would continue. Today, I kept my foot on the pedal and the car turned off. This only happens when I'm traveling at 40+ mph.

I'll have to replace the accelerator pump if all else fails.

 

[rocketengine]

Update: So I removed the air cleaner, and looked through all the many vacuum lines and hoses. I eventually noticed one of them was dangling. One of the below pictures shows the line. It has an elbow type connector and is located between the carburetor and the distributor cap on the driver's side. I dug some more, and noticed there was a nipple somewhat near, so I connected them. Can anyone tell what this vacuum line is and if I connected it to its proper location?

After connecting it, I took her out for a spin. It still did the same thing though. Previously, when I felt the engine was going to bog/hesitate/die, I would remove my foot from the pedal, and the car would continue. Today, I kept my foot on the pedal and the car turned off. This only happens when I'm traveling at 40+ mph.

I'll have to replace the accelerator pump if all else fails.

 

[rocketengine]

There is an emission valve called the canister purge valve. It is a vacuum controlled valve and when it starts to go bad can cause hesitation at speeds around 40 MPH. When it completely goes bad, you will have terrible fuel mileage and black smoke at idle. The loose hose you found looks like it might go to the solenoid that controls the EGR. It is not easy, but if your car still has the diagram for vacuum hoses, you can track it down.

 

[88hurstolds]

The loose hose goes to the EFE valve.
Check to see if the EFE flapper moves freely and isn't stuck closed causing excessive intake manifold heat and vapor lock.

I am assuming that you replaced all the vacuum lines first and looked for leaks with starting fluid to solve the whisteling issue before checking back here???

Are you sure the lockup isn't engaging at 37mph and sticking when you decelerate causing the stall?

Your problem can stem from a number of things and all you are going to get here is tons of speculation since none of us are physically there...

If the car has over 100k miles or has sat for some time in its life chances are you need to do standard maintenance.
Rooting around with your minimal changes could have cracked your dry rotted vacuum lines.

Also this is an EGR/emissions depedant engine and will run like a dream and get sufficient fuel milage if properly taken care of.

Most people are incompetent and rip the 307 out or gut the emissions equpment and slap an Ebrock carb on and wonder why they have poor performance still.
Air/fuel ratios are off and sh*t goes downhill from there... these engines were designed to compete with fuel injection and lasted until 1990.

First and foremost get a CSM.
Then...
Change ALL vacuum lines and properly route to the CSM or visit here:

http://www.gbodyolds.com/forum/showthread.php?297-Vacuum-and-Emissions-Diagrams

If it were me... at minimum change:
Plugs/wires/cap/rotor and ignition module
Change the EGR valve and clean out the EGR passages of carbon with a wire in the intake manifold, they cake up with carbon and NEED to be cleaned out. This engine is dependent on proper EGR operation.
Replace the fuel pump
O2 sensor, AC Delco ONLY, not cheap China sh*t.
Rebuild the carb
And most importantly make sure the CAT isn't clogged.

If all these are done and you still have issues double check to make sure they were done properly then check back but these need to be done regardless, its part of owning a computer controlled carburated vehicle.

Also, Google is your friend, it's best to do the research on your own and familiarize yourself with everything first before asking questions so you are aware of the lingo. Chances are you will find your answer since every question has pretty much been answered already...