slows when driving uphill

[livnhot]

when driving my 1998 k2500 4x4 truck 5.7L. It goes fine until i start to go uphill. My tranny shifts down and the engine revs higher. It feels as if the truck is dragging. I loose speed and it won't pick up. If i back off the throttle and tranny shifts to a higher gear it seems as if I can go faster. Low rpms' seem to run better. I have looked at and replace air filter with a k&n , changed 2 bank 2 oxy sensor. Check engine light goes on, After i shut off the truck and it sits for a while check engine goes off. I had the o2 sensors all looked at and the mechanic said they were fine. Need help to fix, cause I am going crazy. thanks

[ronaldk]

sounds like trans maybe slipping in lower gear.

[jdmccright]

get/borrow a OBD code reader and find out what code is being thrown...that's what the mech should've done first. Could be anything at this point...post the code(s) for us once you find out. Good luck!

[ronaldk]

i agree you should check codes. my wife has 97 blaser she loses 1st & 4th gear intermit and codes servos but i know its brain i just dont want to spend $100 then $100 to flash to veh by dealer. but it seems to reason if your eng develops more rpms that should increase you speed (your eng not bogging down )or at least pulling power and nothing else can accomodate lose of power to back wheels (and not brake apart) i again suspect trans. which is told what to do by brain. get your codes and go from there most auto part stores will put code reader on for free just write down codes

[bracketshark]

check your fuel pressure also. I know that sounds funny since the truck revs up when it down shifts, but trust me low pressure cause strange problems.

[ronaldk]

I read your op again and you say check eng is on what are your codes? I agree if you lose fuel pressure it can bogg, also if air flow is wrong same thing, check or clean maf sensor. cat could also be getting plugged up, a restricted exhaust will cause loss of power also

[livnhot]

Hello All
I finallygot the codes for my check engine light.

Code:P0151,P0137, P0131, P0157

I had my bank 2 sensor 2 replaced. no change
They are all about the same.
1. O2 sensor defective
2. fuel system running lean-check other codes first
3. Engine misfire condition repair
03. Engine Vacuum leak or mis fire-repair
04 . fuel pressure very high or low-fuel pump or pressure regulator
004. Low fuel pressure-fuel pump defective.

This is the code i got. Don't know much about fixing them. I also hava a K&n air filter

thanks eeryone

[ronaldk]

i looked up your codes and each code is for one of your 4 02 sensors. I find that impossible that all your sensors could be bad so check any fuses asso. with 02 sensos the fuse labeled eng-1 is 20a and feeds sensors also if that proves to be good check blk wire on 02s for ground. but usually 20a fuse. if you are running lean because of low fuel pressure or vac leak you may get 02 codes. so as others have said check fuel press at rail check all vac hoses and check 20a eng-1 fuse. good luck

[Chevy-SS]

I haven't heard anyone mention to replace the fuel filter. That is the very first thing I would do.

If no joy, then I would take to reputable mechanic for further check, but sounds like fuel pump to me.

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[jdmccright]

A check of the fuel pressure will show if there is a restriction in the fuel system (filter, pressure regulator, pump). The codes are pointing to a bad O2 sensor or wire (bank 2, sensor 2 is the post-cat sensor). Check the wires (three-wire: 12V, ground, and signal) to the sensor it is showing as bad. Then swap the good sensor with the other on that same side and clear the codes. If it reappears and is the same code, then the cat is likely bad and due for replacement. You don't mention how many miles are on your truck but the O2 sensors on GM trucks tend to need changing after every 100k miles. And a bad sensor can ruin a cat if not changed out.

[stev12]

Originally Posted by ronaldk

i looked up your codes and each code is for one of your 4 02 sensors. I find that impossible that all your sensors could be bad so check any fuses asso. with 02 sensos the fuse labeled eng-1 is 20a and feeds sensors also if that proves to be good check blk wire on 02s for ground. but usually 20a fuse. if you are running lean because of low fuel pressure or vac leak you may get 02 codes. so as others have said check fuel press at rail check all vac hoses and check 20a eng-1 fuse. good luck

Hi livnhot,
Did you get it fixed? I have 1993 olds and it is also showing similar symptoms. Light comes on long uphill and goes away once I reach the top of the hill or stop the car. Scan shows code 13 (o2 sensor) and 44 (lean exhaust). The car has 187K miles. I don't think o2 sensors have ever been changed before. My mechanics estimates 180$. I am wondering if changing o2 sensor solved the problem for you or not?
Thanks!
steve