stalling out when hot?

[jrowe96_2.2]

Ok heres the problem...i have a 96 s10 with a 2.2 auto and when the motors cold it starts up and runs strong but after about 15 min or until engine is fully heated up ill notice the oil pressure gauge on dash drops to the red and check gauge light comes on and at same time if i come to a stop light or sign the motpr will start to sputter and backfire through air intake it sounds like and stall out...then it will not start back up umtil it sits for about 45 min or until cools down then the process repeats itself. The only way i seem to keep it from stalling at idle when hot is to put in neutral and keep rpms up. It also seems to be worse in summer then winter...I am a mechanic but just was given truck from someone so i personally havent had time to diagnose but i do know the icm was changed and so was oil pump. From searching on internet i see this is a problem that many have but have yet to find it so im hoping someone can give me some help and in the mean time ill try some test on it and keep updating thread. Thank you to anyone who can help. Ps-have been told could be a faulty oil pressure unit sending faulty low pressure signals and cutting off fuel but who knows

[viggy58]

based on my knowledge of the 4.3 and 5.7L engines, i'd say a faulty ignition control module might be the culprit. it is the same part on both motors, and can fail under high temps. i dunno about the 2.2 though. the oil pressure issue makes this a little tougher to diagnose though.

how many miles on it? and why was the oil pump changed?

does the drop in oil pressure seem to cause the stalling, or vice versa? i mean, as the engine stalls, the oil pressure will naturally drop. is that what is happening, or is a drop in oil pressure causing it to stall?

how did the oil look at the last change? any metal in it? is the oil pan in good shape? ie not dented up? i would def do a fuel pressure test and a compression test as some free diagnostic paths...

[jrowe96_2.2]

Well i still didnt get time to do any diagnostic test i did hook up a scanner and got a p0440 code which isnt much but while observing the info on the scanner while it was running i noticed the tps sensor reading and when i give the truck gas the injector readings go to 0 for a second and the truck cuts out when i get to about 48% throttle i couldnt go any higher then 52% on the tps % without it cutting out. The oil pump was replaced by previous owner bc they assumed low oil press meant a bad pump but it made no difference...hopefully i can get more info and someone can help me out. Also does that half throttle mean a bad tps sensor

[jrowe96_2.2]

Also the mileage is 156,000 and today it didnt even have to warm up for the oil pressure to be in the red and even with the low reading theres no tapping making me think its a faulty sending unit...also would it be wise to replace the tps after the readings it gave me today and not letting me go above 52% without the truck cutting out

[jrowe96_2.2]

This sat ill get to work on it all day but for now its the same no power the motor just wont rev without cutting out and when its hot ill be lucky to have it idle when in drive at a light...seems similar problems have been fixed with o2 sensor and also replacing a cat on another so maybe thats where i should look next...the codes were for evap not reaching vacumn and an emissions code so both the cat and o2 sensor seem logical. Again any help is appreciated and after i work on it sat ill post the findings...thanks everyone

[jrowe96_2.2]

Tomorrows my day off and only chance to work on my truck at the shop i work at and use all the diagnosis equiptment we got there...when i get home ill post up my findings and hopefully someone will see something that will help them diagnose my problem bc im at my wits end and really need this fixed its my only transportationa nd its so bad i have it off the road bc its not driveable so why keep paying insurance till i fix it. Ill get the codes using our snap-on modis, also the fuel pressure, spark tester and if i can find one a mechanical oil pressure gauge. Ill try to get all readings when cold then hopefully it will act up and stall out when hot and ill get those readings as well. Please follow my postings and post any help that you can cause god knows i need it

[jrowe96_2.2]

I got a p0440 code when scanned which is a evap code and i did have a bad smell of fuel in the cab so instead of disconnecting lines and dropping tank i just decided to pull the bed instead...in which i found the pump was replaced with an airtex pump and the plug was spliced with loose butt connectors and electrical tape so needless to say it needs to be done properly and then ill retrace all fuel and return lines along with the vacumn canister by the tank. And on top of it the i have a terrible exaust leak at the flex pipe that runes after the exaust manifold which is causing a terrible loss of back pressure. After i fix these little problems ill post back to update and if anyone else has an idea please feel free to help