92 Buick Roadmaster Station wagon "surges"

Hi, I could use some clear suggestions.
My 92 Buick road master station wagon with a 350 engine and TBI surges. This means I am going alone the highway at 55/60/65 and you
can feel the car just slightly trying to go faster then slower then faster then slower. Nothing which has an effect on the speedometer or the tack. But I can feel it.
Combined with the above is the additional symptom. When first bringing the car up to highway speed; it hits about 55 then really surges. Bad. Feels like not enough fuel for the engine. I must floor the gas, then it clears up and all is ok from then on except for the previous mentioned symptoms.
Oh, there are NO error codes when I test for them.
I have changes the dist cap and rotor and am in the process of plugs and wires. I am trying to do 2 plugs a day ( have 6 to go). They are hell to replace. I have also retimed and set it to TDC.
My thoughts are running alone the lines of the Ignition coil ($16 us) or the injectors (2 at $35 each).
I have also considered the O2 sensor (but no error code) and the TPS (but again no error code).
Has anyone else had problems like this? What was your solution?
Thank You ---- Dan
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dan wrote in alt.autos.gm

I had a Plymouth Voyager that would exhibit similar characteristics, except that as time went by the surging at 60 plus got a lot worse. That threw out a code for the heater circuit on the 02 sensor. Replacing the 02 sensor cured it up. The first time it happened I paid for 3 hours of labor for trouble shooting it at the dealer. But the sensor was under warranty. The second time I spent an hour of my own time checking all the wiring, and bought a sensor myself. I also put in new plugs, wires, distributor cap and rotor, all to no avail. Could also be the fuel pump, according to a website with some trouble shooting on it.
--
Dick #1349
Damn it . . . Don't you dare ask God to help me.
  Click to see the full signature.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:

I had something like this that since I drove alone on the highway, no one else was with me to feel it. I'd often just set my cruise control to 55 and lean back, but on a very smooth highway with supposedly a constant speed going down the road, I felt something that I kept describing as 'slight loss of power, slight gain of power, slight loss of power, etc.'-lasting about second each interval. It was rhymthic and constant, but very subtle. I ended up figuring out what it felt like to better describe it:
"It almost feels like the car is breathing."
Sounds similar to a thing that was happening in my 3300 91 Olds Ciera, as well. I don't know WHAT brought about the fix, but it vanished about a day after having an intake manifold gasket replaced--as well as about a month after a tune-up and transmission flush. So it could be just about any of the three things, or none of them, that solved it for me.

I think my Ciera was doing the same as well. I actually haven't driven it that much in the last few months (since the gasket) to be able to quote whether it's still doing that or not, but I was told by a shop that my fuel pump was operating on the 'low end of tolerance' a few years ago--haven't gotten it checked since, though. Could tie in with another poster's thoughts on it being a FP issue.
*shrug* But I'm far from being an auto expert, though.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
Dan wrote:

This is common on this era engine - no codes.
Sounds like a dying MAF. The fuel/air mixture is electronicaly controled, so when the main sensor gets old, it can't keep a steady idle.
Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload
wrote:
The Solution, So far so Good
I still have had no Error codes. Have changed the coil, Dist Cap, and Rotor plus the TPS. Still had same symptoms. I replaced the plugs and plug wires. A really time consuming job. The old plugs were gapped at greater then .075 I gapped the new plugs at .035 After replacing the plugs and wires, the surging went away. Still have not touched the 02 sensor. I still have a Injector that drips when the engine is off. I assume it leaks when the engine is running. I will replace it when I have the time.
Just thought I would let you folks know what may have fixed the problem.

Add pictures here
<% if( /^image/.test(type) ){ %>
<% } %>
<%-name%>
Add image file
Upload

Motorsforum.com is a website by car enthusiasts for car enthusiasts. It is not affiliated with any of the car or spare part manufacturers or car dealers discussed here. All logos and trade names are the property of their respective owners.