QuestionDear Wayne,
This may be a little long, but I feel that some background information may be needed to help solve this problem.
First off it is a 91 Pontiac 6000 LE with 206,000 miles on the clock. The engine is quiet and used to run very well. All oil leaks have been repaired as well as new timing chain while replacing gaskets and seals. That was at 175,000. A couple new injectors as well as crank sensor, fuel pump were previously replaced.
Some backgroung information about me. I am a mechanic also, however this problem has me stumped as to whether it is ignition, fuel injectors, or transmission. I do not have a lab scope available to check anything either, that is what is making this difficult for me.
About one month ago, my car started to miss upon acceleration and buck violently cruising at 65 (that was when it was real bad) especially if lightly accelerating from 65. I mean it would buck BAD.
I started checking the plugs and wires and discovered that the plug wire boots were dried up and cracked. Hell, it was like looking at a fireworks show at each plug. Sparks were flyin' everywhere. I said, that's my problem. I replaced the plugs (didn't look too bad) and the plug wires with NAPA Belden Plug wires (they smell good), the Blue Max ones. That didn't fix it. I let the car sit over the weekend and drove my other car.
On monday morning I started the Pontiac up and let it warm up for a couple minutes while getting my son off to school. I get in the car and notice that the air coming out of the defroster vent is not even warm yet, I figured it was pretty cold out, no big deal. I drove to the gas station 1/2 mile away, left the car running (I know bad thing to do) and put 10 gallons of gas in the car. After paying I get in the car and the air is still blowing very cold. I open the hood and remove the radiator cap to discover there is no coolant in the radiator. I go back in the store and buy some coolant and start pouring it in. It is running out the bottom as fast as I am pouring in the top.
I took my other car to work that day and when I got home that night I checked it out and the lower radiator neck broke off the 2 year old radiator. I figured I could solder it back on. I pull the radiator and discover there is transmission fluid in the radiator. I thought, Oh No! I checked my transmission fluid and it was overfilled and the fluid now looked light pink.
So, I replaced the radiator as well as draining the trans fluid and replacing the trans filter and pan gasket and filling it back up. Drove to work the next day and did a transmission flush also. When I dropped the trans pan, there was very little dust in the pan and no chunks of metal. That made me feel good. By that I have to assume that that transmission had to have been rebuilt before I bought the car. I bought the car with 150,000 miles.
That seemed to fix the problem. Those repairs were done 2 weeks ago. Today, the violent bucking returned at 65 mph and it would come and go. For the last two days I have noticed I have noticed a rapid vibration. I balanced my tires which were really out of balance. That took a little of it out, but there is still that rapid vibration. Almost like going over rumble strips. Could that be the torque converter? And by the way, the TCC solenoid has been replaced with a GM unit about 15,000 miles ago. If so, would that cause the violent bucking at 65? Or is a fuel injector or two taking a crap on me? The bucking is not constant, like last time, it comes and goes. I have replaced the module and coils with known good units and they made no change.
Sorry to make it so long, but I felt the more information you had, the better. Thanks for your time.
Alan Klotzbach
AnswerHello Alan, sorry it has taking so long to answer you. but I have some bad thing going on here. got one brother in the hospital, and last night had one brother to passed away.
so it has not been a good week for me.
Ok have you checked the EGR valve, check the vacuum line going to the MAP sensor could be closing up at hight speed,
also check the vibration damper.
