Limp mode, '97 2500 454 Suburban
 

Sometimes it goes to limp mode but no engine light. Sometimes I can restart and it's OK. Today I unplugged the battery, and it worked....Could it be fuel pump?

Re: Limp mode, '97 2500 454 Suburban
 

What is limp mode, and what are the symptoms?

Typically a fuel pump on its way out works better with the tank full of fuel and before it heats up. Easy to test fuel pressure at the port with a gauge.

What is the condition of battery cables, your grounds, when was the last tuneup?

Re: Limp mode, '97 2500 454 Suburban
 

Never had one of these years go into limp mode and have had fuel pumps and distributors die on me. With the fuel pumps it just quit and would not go again. Distributor just ran like poo, or if it was module it just died.

I amjust guessing. That limp.mode on these earlier years would be throttle body related, but that is just a guess..

Re: Limp mode, '97 2500 454 Suburban
 

Not sure Bill, his 97 should be black box MPFI, I'm not saying there isn't a limp mode, but we need some more info to help figure it out.

Black box isn't super advance but it is a step above OBD1 TBI stuff and if there is a problem, chances are there may be some pending or stored codes.

Re: Limp mode, '97 2500 454 Suburban
 

It may not be "limp mode", it just will not take gas and barely move. First time it did it was low on transmission fluid, filled it up and was find, transmission never slipped. Few months later did it again but transmission level was fine, turned it off and started it back and it was fine. Last time turning it on and back on a couple of times did not work, unhooked the battery and it worked fine. Have not used it since and it's too cold to run a scan right now. Thanx for the input.

Re: Limp mode, '97 2500 454 Suburban
 

I bet it’s the throttle position sensor(TPS)

Re: Limp mode, '97 2500 454 Suburban
 

Starts and idles fine.