I just bought an 85 T/A. I Drove it 600 miles back from Portland OR To Montana. The car has no power at over 3500 RPM. If you happen to be in overdrive when you stomp on it, the car bucks and vibrates, but doesn't really go much faster. It has the 305 LG4 motor in it. 700R4 trans, the motor and trans were supposed to have been rebuilt 1500 miles ago, but on the same token the car had only been driven 1200 miles in the last seven years. I changed the thermostat becaue the temperature guage was reading 160 max, and the catalytic converter was glowing orange one morning when it was warming up. I put in a 180 degree stat, but when we ran the car again the temp guage was still reading 160. Item of note: When the thermostat was being changed we noticed that the sending unit in the thermostat housing was not seated all the way and had some crusty VERY hard white goop on it, so we pulled out the sensor and cleaned it up with a wire brush but it still wouldn't go all the way in, there are about 1/4 of an inch of threads left. Is this a problem, and where do I go from here. STUCK! Thanks for any suggestions.

I just bought an 85 T/A. I Drove it 600 miles back from Portland OR To Montana. The car has no power at over 3500 RPM. If you happen to be in overdrive when you stomp on it, the car bucks and vibrates, but doesn't really go much faster. It has the 305 LG4 motor in it. 700R4 trans, the motor and trans were supposed to have been rebuilt 1500 miles ago, but on the same token the car had only been driven 1200 miles in the last seven years. I changed the thermostat becaue the temperature guage was reading 160 max, and the catalytic converter was glowing orange one morning when it was warming up. I put in a 180 degree stat, but when we ran the car again the temp guage was still reading 160. Item of note: When the thermostat was being changed we noticed that the sending unit in the thermostat housing was not seated all the way and had some crusty VERY hard white goop on it, so we pulled out the sensor and cleaned it up with a wire brush but it still wouldn't go all the way in, there are about 1/4 of an inch of threads left. Is this a problem, and where do I go from here. STUCK! Thanks for any suggestions.

I went through a simaler dissision,and after a lot of thinking I sold the car and bought a real Pontiac,1st Gen bird,then again you could always drop a 383 stroker chevy in....

You're getting unburnt fuel into the cat.

I've got an 86 w/ the same POS 305HO & 700R4.
Will be conerted to a 400 Poncho & TH350 this year for my Son.
These 700R4s are SH#T!

Well... the sending unit for the temperature gauge should be in the left cylinder head between cylinders 1 and 3. The coolant temperature sensor in the thermostat housing sends information to the vehicles computer, but has no effect on the gauge. If you feel that it needs to be replaced, you could purchase a new thermostat housing.

If the cat is glowing and the vehicle has no power, you may have a clogged cat. For testing purposes, you need to remove the cat and then drive the vehicle to see if power is restored. You may have to remove the entire y-pipe in order to do this, but that is where I would start.

It does sound like a clogged catalytic converter. Will the engine even rev over 3500 at idle if you gas it?

Get a hold of a backpressure guage. They thread in where the O2S goes. It should only read slightly above zero at any given RPM. If you have anything above 1 psi, the cat's plugged.

Turbo 700's can be made to live in a 10 second car. They're not as weak most people think, they're just finicky with their TV adjustments. Check out bowtieoverdrives.com for some 700 goodies.

Okay, I have more information that may help you help me (Thank You!). We decided that the car was missing, so , we pulled the spark plugs and guess what most of them were gas fouled. Two of them had bridged electrodes so they were not firing at all. I'm fairly certain that this happened during the 600 mile trip back from Oregon. Would a clogged cat cause the plugs to foul? I changed the thermostat housing and the coolant temp sensor, the guage was still reading below 160 before we pulled the plugs out. Also my dad says that the distributor No. 1 plug should line up directly with the plug in cylinder No. 1. If this is true then the car could be out of time as well due to the distributor No. 1 plug is off about 1 inch from lining up with cylinder No. 1. I'm beginning to get confused. Can anyone suggest a process? What order should I replace or test things in to save time and money? Thanks again for all of your input guys.

<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">Originally posted by CAB:
It does sound like a clogged catalytic converter. Will the engine even rev over 3500 at idle if you gas it? </div></BLOCKQUOTE>
It didn't really rev, kind of climbed up the tach, spark plugs were fouled, now we'll get down to brass tacks