I would follow the already given advice and change the PLUGS and WIRES first. I had a wire that died on me and my 96 ran like A$$. I spent money i didnt need to trying to fix problems that weren't there. Follow Occam'* Razor
http://en.wikipedia.org/wiki/Occam's_Razor
and try to take a Scientific Approach to car repair......

As noted on another thread, cleaning the MAF sensor is quick, easy and cheap. Use special cleaner by CRC for MAFs. Kudos to Sandrock for putting me onto this one.

MAF sensor is black plastic thing, on throttle body, unplug connector, remove 3 phillips screws and it slides out. Should see 2 little short, delicate wires in round hole. Spray clean those. It was like putting on a hoppup kit on mine. Way cool

Thank you all very much for the great advise. I never thought about cleaning the MAF sensor. Until i joined these forums it never entered my mind. I also appreciate the detail of how to clean the MAF as well. I will certainly start with plugs and wires and go from there. I will clean the MAF sensor. I have access to coil packs that are in very good shape at no cost. Should I go ahead and use them with that in mind? Also, it takes a 5.5 mm socket for the coil packs? Not just a 5mm but 5.5mm? I've, embarrassingly never seen a 5.5mm before. I guess I can pick one up at Advance Auto or Auto Zone I assume? Again, thank you all for the great advise. I can wait to get into this thing and get her running good!!.


I wish I could find a forum this great to help with my '96 Mercury Sable.

Just wanted to let you guys know that many of you who predicted that the plugs and wires should be the cure were correct. I made time to change the plugs and wires today and the engine runs great! Funny thing is the wires that were on there were numbered as to what cylinder each belonged to. Leading me to believe that these wires were still the original factory wires that came on the car! The wires had plastic heat shields on them and I thought I'd try to take the heat shields off and put them on the new ones and they were so brittle that they fell apart before I could work them off. haha. Also the plugs were Bosch platinums and looked like crap. I've heard bad things about Bosch plugs. I replaced them with AC Delco plugs and Autolite lifetime warranty wires.

Now the car is running nice and smoothly. I'm a happy Bonneville owner. For now (knock on wood)

Thanks for the Update..but....You'll be back
If not for repairs...for the MOD bug...LOL

haha. I'm sure I'll have plenty of future questions. But for the record, I don't plan on leaving! There is way to much wisdom, advice and willing helpers on this forum to leave! I'll stick around just to continue learning about my car and use the advise I learn for future reference!

It'* very likely, People never seem to replace plug wires for some reason. The stock wires usually have "Packard" on them (A GM division that made electrical parts...sad...all that is left of the grand old Packard brand) and yeah, the plastic shielding usually does fall to bits after being cooked. When you can, I would recommend getting more of the corregated plastic tubing and replace the stuff that fell apart. It'* not really there for heat shielding, it'* to prevent chafing on the insulation from other metal parts of the motor. When GM really wants to heat shield something, they will do tin work (like the metal sleeves around the plug boots) or use a metalized fiberglass cloth to insulate a part from heat.

Welcome to the wonderfull world of the Bonneville

So I seem to be having a similar problem here. I realize now that i've had a few more than anyone would want to... but this is only the second time i've driven it for an extended period of time at interstate speeds.

Driving is generally a breeze, no problems whatsoever until I am going up a hill. When I have to downshift for power, it'* fine, but when it shifts back up (assumingly into OD) it will only go to about 2000 RPMs before it bounces just around 1800, 2000 over and over and sort of jerks the car as if i were pumping the pedal. if I press harder on the pedal or push it sharply, it will downshift and accelerate like a madman. The problem only occurs on the bottom end of the upper gear. Could this be the wires as well or does it sound more complicated?

Like I said, generally it operates fine until going uphill around 65 mph

Most ignition problems are more noticable under load at low rpm'*. That means climbing a hill in OD.

Plugs, wires, coils. 95% of the problems with symptoms like yours come back to one of those three things.

willwren knows his stuff so take his advice but from my own experience, my car was doing this same thing. i replaced the plugs and wires and the car runs great. Quit doing that all together. So, that should be good news for ya.