i have a 98 gmc sierra 3500. it will start and run great until you turn it off. to get it to restart you have to disconnect the battery or wait approx. 30 min to an hour with out disconnecting the battery then it will start and run fine until you turn it off again. i don't have a check engine lite on, but am getting a p0122 throttle position sensor switch A ciruit low input on the tester. the truck will turn over and fire for a second the dies. any help would be appreciated. will this sensor cause my problem? thanks, rick

 

YES IT WILL CAUSE YOUR PROBLEM

I had the same problem and changed that 2 screw sensor on the side of the thorottle body and it cured all my problems

 

i've been trying some other stuff like chasing down wires and grounds to make sure nothing is loose i'm gonna change the sensor today. we'll see what happens

 

GOOD LUCK!! Hope that fixes your problem post up and let us know how it works out.

 

changing the tps sensor didn't work. truck still starts once then won't restart until you disconnect the battery. the other thing i found out is the truck won't restart after a battery disconnect if its hot. it has to cool down a bit then starts and runs great. so far i've put a new fuel pump, fuel filter, tps sensor, and cleaned up some wires. what about ignition module? don't know where (distributor cap?) or what it is just something someone said to me. any help out there? thanks, rick

 

Lets narrow it down here... When it turns over and does not start, Have you checked fuel pressure, are the injectors pulsing and are you getting spark?

 

i will turn over and fire for about a second or two. acted like fuel to me, thats why i changed the pump. plus it was dirty anyhow. i haven't checked the fuel pressure. will do that tomorrow, but don't expect thats my problem being that the pump and filter are new. drove it around this morning and am curious if it has thrown that p0122 code again. going in my brothers shop tomorrow. will update this post tomorrow night with what ever we can find out. we don't have a computer diagnosis machine with the flow charts and what. we have been thinking about investing in one,now might be the time. and suggestions on that are much welcome too. thanks, rick

 

If it fires and then dies a couple seconds later, that sounds like the Passlock 2 system to me.

Try the Passkey 2 security relearn on page 2 of this site.

peace
Hog

 

tried passkey relearn with no success. my security light goes out after only a couple of seconds. i still waited around about 11 mins after each attempt to start, but no luck on the forth start. worse yet i decided to change intake manifold gaskets after noticing a leak . just to find that two good sized portions of my manifold were gone due to corrosion. only 90k miles on this truck, i guess some one used the wrong coolent. what a suprise. new manifold on tuesday then back to the starting problem. anyone know where i can find torque values and pattern for my manifold that would be a big help. thanks in advance

 

OOOPS I forgot the link
http://www.bsecorp.com/files/techtips/ST9303l.pdf

peace
Hog