so about 5 months ago, i had an engine replacement due to a blown bottom end. when i got the car back, i was told that i would need to break in the engine and the mehanic said i would need to warm up the car in the morning before driving as a precaution and said i would only have to do this for about 2 weeks and i should be fine. well now, in the mornings, my temperature gauge stays below the red line until after ive driven it for about 10 minutes, then it starts to go up.well until the needle actually goes up a bit, the monte tends to run really really sluggish at low and mid rpms!idk why it does this.even after the gauge has gone up, the monte runs a bit sluggish when im only giving it a little gas(low rpms).It drives like it choking. other than that, once shes warmed up and at mid/high rpms, she runs good, except for an occasional hard shift in the tranny

so that would be problem one

problem two would be the tranny giving me occasional hard shifts in the 'D"(when the car is accelerating)
it also gives me frequent hard shifts when shifting from park, to reverse, or from reverse to drive.

problem three
when im in reverse, every now and then, i hear a loud groan noise comming from the car somewhere?i dont know what it is.

I am already planning on buying a new thermostat to reduce KR and its a possible fix to problem 1. but does anyone have any other sugguestions on my monte's issues?

 

Was the engine replacement a brand new engine, or a used engine? Also were all the sensors changed to be new as well?

 

My first impulses:
Check your transmission fluid, make sure you're not low.
Check your coolant (when the car is cold, pop the radiator cap and see if it's filled or if it's low). Potentially, all the air may not have been bled out of the system

I almost wonder if you have a failed catalytic converter, but it may be too premature to consider that.

Chibi's points are also valid. If it's a used engine (even if it was rebuilt), it may not have been tested the way a "new one" from GM would have been. Also, if it's using old sensors, the condition of those sensors is unknown and may be the source of a problem by providing your car incorrect readings.

 

No, it was not a new engine, i got the whole bottom end from a crashed impala.opened it up, cleaned it all out.the whole top was rebuilt, 2 weeks before i bought the car.

i know all gaskets were replaced but im not too sure about the sensors.ill ask my mechanic a little bit later

 

Reason I ask is because the front bank o2 sensor and the MAF sensor could cause some of the issues.

 

is it a hard fix?

does that have anything to do with the tranny issues as well?

 

Check your transmission fluid

 

i should be checking if its low right?
how do i do this?


will getting a new o2 sensor be a solution to problem one?

 

Low, Dirty, Smelly, etc.

Use the (I think red or pink) dipstick toward your firewall.

 

ok i checked it and its somewhat dirty.also, it filled above the line that say "max operating level"