Hard start/Rough Idle & Trans slip

1996 GMC 3500 pickup 5.7 350 4dr long bed 2WD
What a combination!!!??!?! First when I try to start it take literally 5 minutes to get started, it's like it not getting enough fuel but then it seems like it's flooded after several attempts at starting i changed the fuel pump about 6 months ago. After starting, it idles at 2000. Then after about 2mins or so it will get back to normal but sometimes i have to turn it off and restart to get the idle down. when driving it will idle up and the trans will slip. driving on the freeway at 60 the trans starts acting funny. I do have a "service engine soon" indicator the service codes are PO122/P1345 & PO118.

Can anyone assist?

Update:::


Replaced the Throttle Body Sensor and the Coolant Sensor runs a little better but still wants to cutoff. I am confused on Code 1345 how can i rectify that???

it all depends on what the code it. you might have something that is making the truck run bad. on my 94 sierra 5.7 litre. the coolant temp sensor was bad. the truck would start fine in the morning but sometimes not at all, then after about 6-10 miles of driving it maybe a little more if you stopped the truck would die out. but if you kept your foot on the gas it would run. your tps sensor might also be acting up causing a high idle at times

Do you have an oiled air filter or has one been used in the past?

Read this if it fits your vehicle

Info - Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter #04-07-30-013A - (Jan 25, 2005)

2005 and Prior GM Cars and Light Duty Trucks

2005 and Prior Saturn Models

2003-2005 HUMMER H2

This bulletin is being revised to add additional model years and to clarify warranty coverage. Please discard Corporate Bulletin Number 04-07-30-013 (Section 07 -- Transmission/Transaxle).

DO THIS:

First, Inspect the vehicle for a reusable aftermarket excessively over- oiled air filter.

DON'T DO THIS:

DO NOT repair MAF sensors under warranty if concerns result from the use of an excessively/over-oiled aftermarket, reusable air filter.

The use of an excessively/over-oiled aftermarket, reusable air filter may result in:

• Service Engine Soon (SES) Light On
• Transmission shift concerns, slipping and damaged clutch(es) or band(s)
• Engine driveability concerns, poor acceleration from a stop, limited engine RPM range

The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur.

When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern.

The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty.

If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs.

Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items.