1996 5.7L P1406 and P0175 - sometimes

[Suburban4towing]

1996 Suburban K2500 with the 5.7L motor - 151K miles. Soon after I bought the truck it started having hard start problems and running generally badly when cold or until turned off and back on (after sitting a little while) when hot. The CEL was on too. Replaced the fuel regulator and had the dealer fuel injection cleaning done before buying a code tool. Turned out to be a bad TPS (hard shifts too - I've learned this is one sign of a bad TPS). Replaced that and everything was good for about 300 miles. Now every once in a while I get a P1406 (EGR pintle position) and frequently get P0175 and P0172. Sometimes when it starts after sitting for a day or two its idles high and shifts hard. Other times it will stall when in drive if started after sitting for a day or two. This last time it stalled twice and cut out (missed?) a few times even after warmed up. Trouble is, nothing is consistent - sometimes runs fine, sometimes it doesn't - and when it doesn't its not just the same symptom. Any help would be appreciated - this is our Summer tow rig AND our soon to be driving daughter's first ride.

[MT-2500]

Originally Posted by Suburban4towing

1996 Suburban K2500 with the 5.7L motor - 151K miles. Soon after I bought the truck it started having hard start problems and running generally badly when cold or until turned off and back on (after sitting a little while) when hot. The CEL was on too. Replaced the fuel regulator and had the dealer fuel injection cleaning done before buying a code tool. Turned out to be a bad TPS (hard shifts too - I've learned this is one sign of a bad TPS). Replaced that and everything was good for about 300 miles. Now every once in a while I get a P1406 (EGR pintle position) and frequently get P0175 and P0172. Sometimes when it starts after sitting for a day or two its idles high and shifts hard. Other times it will stall when in drive if started after sitting for a day or two. This last time it stalled twice and cut out (missed?) a few times even after warmed up. Trouble is, nothing is consistent - sometimes runs fine, sometimes it doesn't - and when it doesn't its not just the same symptom. Any help would be appreciated - this is our Summer tow rig AND our soon to be driving daughter's first ride.

To repair it you will need a engine capable scanner and some good repair info for flow chart on code 1406.
Can be caused by egr valve or iac motor dirty or miss adjusted and dirtyTBI butterfly.

Factory repair manual or a all data online sub will take you threw the repair flow charts for the codes.
http://www.alldata.com/products/diy/index.html

Start with the 1406 code repair.

Let us know how it goes.

[Suburban4towing]

Thanks - I'll look into that.

Any other comments are welcome.

[MT-2500]

Originally Posted by Suburban4towing

Thanks - I'll look into that.

Any other comments are welcome.

You are welcome.
You might give the egr and tbi and iac a good cleaning to start with.
Good luck