Well my brother is having trouble with his truck. Its a 00 or 99 1500. Its got the 5.3 (I think their 5.3, not the smallest, but not the biggest). WHen he floors it the car will not go above 3500 rpm, he says on a good day it will go to 4000 rpm but its like its stuck, this happens in drive and in park/neutral. He recently had the transmission rebuilt and I have no idea what would be causing it. Anyone know a truck tech site or perhaps know what the problem is? Thanks.

 

Sounds like it is air restriction. Check your air intake and filter.. make sure nothing is craked in your intake tubing. something that is craked might cause it to bend and cause restriction. Does it idle fine? Makes sure your Mass Airflow Sensor is hooked up correctly and tightly clamped. Your mass air flow sensor is the gadget that is attached right after the air box (it has some wires connected to it). Thats all can think of now.

 

If this started happening soon after the trans rebuild, I'd be looking in that direction first.

 

Thank you for the quick reply. Im the mechanic here in this family and my brother is clueless. Im familiar with LS1's but my specialty would be LT1's since I threw one in my 91 camaro. I have not checked his air intake. I was thinking of checking his cat conv. and fuel pump. His car idles perfectly, vacuum lines all seemed intact. I have not checked to see if his MAF is plugged in correctly or if the screen needs cleaning. I will check all the items you listed but is there anything else that could be wrong? The truck is not throwing any codes, thanks.

 

He rebuilt it about 8 months ago, don't think thats the problem, after trying the other noted items, im gonna have him go back to AAMCO and have them check it out, he said it has a warranty still on the tranny. But I don't think the tranny would stop it from revving past 3500 in neutral, its almost as if he is hitting a rev limiter or something.

 

yup he is hitting the rev limiter , for some reason the truck isnt telling the computer that he is in drive. so it thinks it is only in park or nuetral all the time, he needs to take it somewhere and have them test that.. the limit in neutral is different then in drive.. 100% right on this one..

 

yay the cats will do the same thing.

 

When the cats went on my LT1, there was a noticable power loss at all RPM's in all gears. It wouldnt get out of its own way. How long ago did this start?

 

my cats stopped up and my truck did that too. mine got to where it would pull line pressure and not shift. check them out, my guess is that they are the culprit.

 

The rev limiter shouldn't be any lower in park or neutral than in drive.

Does it bounce when it gets up that high, like it's bouncing on a rev limiter? The pre-03 trucks have a pretty hard rev limiter that's hard to miss.

I'd check on the intake and exhaust to make sure there's nothing plugged up there.