when i get up to around 55mph the truck starts bucking sort of and can't get past 55, once awhile i can get past it no problems but most of the time i can't. I've been told a need a new egr and it might be the problem, i want to make sure this is the problem before i spend 230$ on a new one. any help is appreciated

 

Make sure that the vacuum hoses are all connected properly no leaks

 

i will. its getting worse, it stalled going up a hill and stalled when i hit 55 and had a really rough time starting again.

 

With the truck safely parked and idling,open the water in fuel drain Tee-valve mounted near the thermostat housing and observe what happens.

If fuel flows and it keeps running-good.
If no fuel and it stalls-the Lift Pump is not working.
Could be a bad LP or a bad OPS.
To test the LP itself Apply 12 v to the ALDL pin G,the LP should run and pump fuel from power flow through the LP relay from ALDL pin G.
Or jumper the relay between the grey and orange wires(I think)the jumper locations are back middle and frt left on the relay connector.

If all is well there replace the OPS with AC Delco ONLY and google OPS relay mod.

 

Do you know your rear axle gear ratio?

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As for the stallinh id try what racer 55 has stated above

 

I'm really new to diesels. my mechanic said it could be the egr. if its not ill try what you've said, but it seems really over my head at the moment. new egr tomorrow hopefully. ops is oil pressure switch? my oil pressure has been normal even though i have had low oil and it stayed the same

 

Sounds like mechanic is new to these too...auto parts stores commonly mistake egrs for cdrs if u go to the store its under egr category but with 6.5s its cdr and is only oil pressure related dont believe itd affect power its located on passenger side up on valve cover looks like a can of chew it says notice tgis end up on the top of it

 

you will still read good oil pressure. the ops has a separate contact to power up the lp that is a weak point. i agree with racer55 i think it may be starving for fuel.

 

the egr is not even connected. seems like you all think its the lp, i will see what i can do when i get home from work. would that be something thats expensive to replace or hard to install?

 

think mine was about 70 for the lp and 30 for the ops. make sure you buy ac delco parts. the cheap aftermarket ops are junk. make sure and test both before you go throwing money at it. there are some informative threads on here on how to test them.

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FYI if it is the lp get one for a 93'. i hear they carry the best fuel pressure.