92 Caprice no acceleration

ok so ive been doing some reading around. My previous post was about changing the gear ratio. I thought perhaps the 2.93 gears were the culprit but reading these forums that may not be the case. This car has no punch whatsoever. I literaly have to put my foot all the way to the floor when coming off a stop light to get it moving and if Im on a step hill have to keep it to the floor just to maintain 60 MPH. I have a tuneup done, changing all spark plugs and wires. I have had a new catalytic converter put on and intake manifold gaskets replaced ruling out any exhaust problems.

I had the tranny replaced its a 4l60E and the mechanic says its a possible ECM related issue. Does this mean that I need to replace it? I just find it really hard to believe that that little box can be causing so much. It shifts fine and im really at a loss and am really tired of throwing money away on this thing.

ok so ive been doing some reading around. My previous post was about changing the gear ratio. I thought perhaps the 2.93 gears were the culprit but reading these forums that may not be the case. This car has no punch whatsoever. I literaly have to put my foot all the way to the floor when coming off a stop light to get it moving and if Im on a step hill have to keep it to the floor just to maintain 60 MPH. I have a tuneup done, changing all spark plugs and wires. I have had a new catalytic converter put on and intake manifold gaskets replaced ruling out any exhaust problems.

I had the tranny replaced its a 4l60E and the mechanic says its a possible ECM related issue. Does this mean that I need to replace it? I just find it really hard to believe that that little box can be causing so much. It shifts fine and im really at a loss and am really tired of throwing money away on this thing.

It can't be a 4L60E if it's a '92, unless it got swapped into it later and if it did, it's anyones' guess as to whether the computer matches the transmission. The 4L60E began use in the Caprice starting with '94. Prior to that it was the 4L60 (no E), otherwise known as the TH700R4.

If it is an 'E', there are two types of computers for it - one uses standard lockup and the other uses PWM lockup - they are not interchangeable.

As for the acceleration issue, check the ignition timing (which on that car should be set to 0' TDC with the computer EST connection disconnected).

Does the engine's RPM seem higher than should be for the speed?

No you are correct it is the 4L60. I was looking at tranny's at the same time as my post as ive been wondering if even after the swap that is the case and was pricing some things.

The only time it seems to idle high and is kind of loud is in the morning on a cold engine. Outside of that its fine. I got a tuneup done on it, and because the changed the sparks/wires and because it ran smoother afterwords I was of the assumption that they did the timing correctly. I would have no clue as how to do that myself, but Im sure with some reading I can. On another note the car has some 22" rims on it. Someone mentioned to me that they may just be to heavy. I REALLY find that very hard to believe.

No you are correct it is the 4L60. I was looking at tranny's at the same time as my post as ive been wondering if even after the swap that is the case and was pricing some things.

The only time it seems to idle high and is kind of loud is in the morning on a cold engine. Outside of that its fine. I got a tuneup done on it, and because the changed the sparks/wires and because it ran smoother afterwords I was of the assumption that they did the timing correctly. I would have no clue as how to do that myself, but Im sure with some reading I can. On another note the car has some 22" rims on it. Someone mentioned to me that they may just be to heavy. I REALLY find that very hard to believe.

with 22in rims you have increased the load to engine ..when at a stop and then hitting the throttle I would expect bogging down...

if this is the look you want I would suggest replacing the rear diff to 3.42 ratio area...

So you think its the rims as well? I really wish I had stock ones to find out. Its the way I bought the car so I cant say if it was doing it before I got it.

So you think its the rims as well? I really wish I had stock ones to find out. Its the way I bought the car so I cant say if it was doing it before I got it.

get some wheels off a scrap yard vehicle and put them on the rear axles see if it burns out..rubber..

if so the 3.43 gears sound like the way to go..

if I end up swapping out rear ends to a higher ratio, do I have to do any other modding? Like to the tranny or anything?

Could the oxygen sensor also be causing this? Im willing to be this has never been changed on this car, and from reading its really prone to rust damage on this year car and should be replaced every 2 years or so.

Could the oxygen sensor also be causing this? Im willing to be this has never been changed on this car, and from reading its really prone to rust damage on this year car and should be replaced every 2 years or so.

the O2 sensors are good for 100,ooomi....if it is the original I would change it ,,,but it should not be the issue you have...

with the diff ratio changed the speedo will read higher than you are actually going ,,,on your vehicle I don't know what needs work to read correctly...

but this is do able..

Ok im at about 190k on this car. so about 90k overdue. I say about because it was at 184 when the speedo/odom stopped working. My wife is already very upset on the amount of money im pouring into this car. Hell so am I. I wish I would have done a little more reading before I bought the 92 with a 305 knowing I wanted big rims. :/ I just never thought it would be this much of a problem. I mean I get passed routinely by VW's coming up the hill, and dont talk about power at WOT. I tried today after changing the fuel filter. It just feels like Im not hitting over 2k RPM's at all.

Heres something interesting. I tried smoking the tires today. Held the brake hit the gas, it did nothing, didnt even stall. If I rev the engine while on the brake I can get the RPMS high enough to get the rubber to break ground, but just stepping on the gas and trying to get them to break doesnt work.

try the scrap yard tires of the 215 75 r15 size to see if it is indeed the larger tires...just the two rears....some yards may allow you to return them...

I had sum what the same problem i had no accleration at all i could push the damn thing faster than it would go if i floored it i replaced cap and rotor didnt work the actual distributor its self was worn out so u might want to try that