Dont know what else to do

[HeavyAsAChevy]

Welcome to the forum! Also, thank you for not getting upset at the request for grammar so it’s easier to understand. That goes a long way here.

 

[udidwht]

If the knock sensor is bad that will likely limit your power due to the timing being pulled (retarded) when under load/WOT.

 

[Tjlracerx]

I have a 94 chevy obs short wide c1500 5.7 4l60 I picked up about a year ago for 400 bucks it had a few problems but she's a keeper lol so far in the past year I've rebuilt the front end, brakes, new radiator, alt, it had already the ac delete and egr delete I did gold series plug wires cap new rotor and plugs don't remember kind it was running great never real keep up with milage cause it seemed good fast-forward to early Feb the trans 4l60 goes out I had another trans 4l60e from a 95 obs so I swapped them ran good for a month then drive shaft goes fix it next week rear-end goes bad so I have swapped both and rebuilt the drive shaft.. the vibration from the rear-end going out made all kinds of things loose and it was running like **** I changed plugs wires cap rotor oil change iac and connection map i have my o2 unplugged now pulled and cleaned temp sensors temp sending switch thermostat it seems to r b running good kinda lost some power somewhere and maybe its because something else is wrong cause im getting 8.5 to 9 mpg and these gas prices are killing me its my daily driver I put about 65 miles a day sometimes less but that's average most times it dont get drove on weekends I drive my wife's gas saver lol im not trying to racer or anything lile that yes I was it fast well at least the power it should have and the most is better gas milage anybody got any suggestions oh ya there's a small cam in it I dont know what kind at least it sounds like it does never pulled it trying to give as much info as I can to readers and 3" exhaust to a 3 chamber Flowmaster out 3" to a y pipe comes out 2 2 1/2 and dumps no headers stock manifolds hope everybody has a good day thanks for all replies hope somebody can help im

Update on the truck. It was the knock sensor o2 plugged back in. Knock sensor has been relocated to the other side of the motor in the same spot its running great. Really seems to help the mileage out. I did have to redo timing. thanks again for all replies

 

[Tjlracerx]

For instance. My truck is a work truck. According to the build sheet it has a 3.08 ratio rear, which means it won't get off the line worth a damn but it will cruise all day at 70 MPH in overdrive (4th) and get good mileage because the engine is turning about 1800 RPM at that point.

If you have a hot cam and a 3:50 or 4:11 rear end you won't get near the mileage I do on the commute. If for some reason your trans isn't making the final shift into OD its even worse and the engine will suck up gas like you would not believe. I was thinking you should rule out a trans problem pretty early in the game.

I get what he was saying on the gearing and knew od was overdrive. did not realize thats what he meant. And yes it goes in od. Its running much better now after changing knock sensor. I never know a knock sensor could throw so much off

 

[HeavyAsAChevy]

I get what he was saying on the gearing and knew od was overdrive. did not realize thats what he meant. And yes it goes in od. Its running much better now after changing knock sensor. I never know a knock sensor could throw so much off

Sensors like that are irritating. I had a similar issue and it was my coolant temp sensor being unplugged.

 

[L31MaxExpress]

For instance. My truck is a work truck. According to the build sheet it has a 3.08 ratio rear, which means it won't get off the line worth a damn but it will cruise all day at 70 MPH in overdrive (4th) and get good mileage because the engine is turning about 1800 RPM at that point.

If you have a hot cam and a 3:50 or 4:11 rear end you won't get near the mileage I do on the commute. If for some reason your trans isn't making the final shift into OD its even worse and the engine will suck up gas like you would not believe. I was thinking you should rule out a trans problem pretty early in the game.

Running 70 mph all stock with a 4L60E and 3.42s 3rd vs 4th was not even 1 mpg difference highway. One of the deciding factors when I decided to go much deeper on the gearing.