cheefzboy

01 Z28 Auto 92K

Car feels restricted when stomping on the gas from a stand still .feels like the back tires kind of skip on the pavement then it shifts into 2nd quickly and bogs down. Then takes off like a bullet. Driving regular speeds is fine unless its less then 15 miles an hour. Gas gauge also randomly drops to E and then back to normal. Cleaned MAF Sensor and screen. This helped some. I Had Tranny rebuilt in December. It shifts quick and firm.

myk

iTrader: (4)

When you say your gas gauge drops does it happen during turns, heavy braking, etc.? My '97Z & '99 T/A do that also.

Any codes? Assuming your car is in good tune, with clean filters, good plugs, wires, etc, I'd take a shot at the fuel pressure. That's my thing. I hate fuel pumps on these cars and I blame them for everything including flat tires...

cheefzboy

Getting codes checked today. Its pretty random when the gauge drops. Some times its within 10 seconds of a cold start, after putting the car in park or stopping at a stop light or some times just driving down the road.

I think its caused by the fuel sending unit. Its a 700 dollar fix at a shop though.

It has never died on me though. Torque is defintaly lacking though. The weird thing is after punching it a few times it starts to run pretty damn good! gotta be gas related huh?

cheefzboy

Got the codes ran:

2 cat defiency codes, the car has no cats though.

02 sensor code, Something about not getting a good electrical current?

garygnu

was the car tuned for no cats?and was the back O2 sensors deleted?

cheefzboy

That car still has cats on it. I think they were gutted and no it hasnt been tuned catless. I have no clue even where the sensors are if they are still there. I did notice that the exaust pipe on the drives side is hanging down a bit and it flat? Is it supposed to be flat? could that be bogging it down?

Also no check engine light has ever come on and today I drove about 20 miles on the highway. Stopped at a friends for a bit and when I started it up and shook and started long after I turned the key. Then the gas gauge went all the way to full for a while before returning to 3/8 tank.

Tommyv8

iTrader: (8)

Yes, the factory Y-pipe on the driver side is kinda flat. It was made that way for floorboard clearance.
The gas gauge problem is the fuel sending unit; we just had that fixed on the Trailblazer.

crazyc1123

iTrader: (1)

Sounds to me like you def have a fuel sending unit issue. You may want to look into just repalcing the entire fuel assembly cause your fuel pump may be getting weak. You could also have a tuning issue as well. You need to figure out whats goin on with the cats and 02's cause a clogged cat can cause a lot of issues

cheefzboy

allright, I'll look into getting it replaced. Also It seems like it shifts too damn much. Usually shifts into 2nd@13-15mph and 3rd@ 25mph or so. Should my shift points be changed. Seems to narrow

cheefzboy

Im thinking it may be the TPS..

* Bucking and jerking of the car
* Idle surging
* Sudden stalling of the car engine
* Hesitation while the driver of the car is trying to accelerate
* Sudden surge in car's speed while driving on the highway

* Engine malfunction indicator light (MIL) is turned on
* The driver of a car experiences difficulty while changing gears.
* The fuel economy of the car drops drastically.
* Causes difficulty in setting base-ignition-timing of the car

It buck/jerks, hesitates, has bad gas mileage and its has difficulty going from gear to the next. Ill try and post a video soon. This is driving me insane

BlackScreaminMachine

iTrader: (17)

Toss a fuel pressure guage, do some WOT runs and see if it drops, record pressure, run a scan tool for data codes and go from there.

razer900

hows your battery/cable and or connections? a bad battery can cause alot of grief with these cars

topgeer

iTrader: (2)

may not be this easy but whens the last time you changed the fuel filter. How many miles do you have on the car? Have you ever had the fuel system serviced?

BlackScreaminMachine

iTrader: (17)

I would Check FP before doing ANYTHING ELSE, with exception of PCM Scan for Codes.

cheefzboy

Found a hole in the exhaust on the right side front by the wheel well. I try checking fuel pressure. I would think if that was an issue it would die and not idol correctly. Which it idols decent I think.

If im not in first gear then slow down the car it bucks then shifts down into first gear then when I accelerate into 2nd the Rpms spike close to 2000 and it hangs up for a second then shifts to 2nd gear.

I do not understand why it ran great for a couple days after cleaning maf sensor. didnt buck or anything. Was making better low end power. Should I try cleaning the IAC sensor or are you not supposed to clean that?

garygnu

its ok to clean the IAC.do you have a K&N oil filter?

cheefzboy

Yes i have a K&N..changed it after I cleaned the MAF. Got rid of the cheap paper one that was letting grass and crud get on my screen. That thing is spotless now as well as the sensors.

cheefzboy

Well I now know what the problem is. its not 02 sensors cats, fuel pumps, etc...Its the REAR END!! I thought I was hearing brake drag in rear. Luckily I just got a rear end the other day for 200 bucks. I was planning on switching it out any ways as it has the 3:73 gears. Talk about lucky

cheefzboy

This should have been a dead giveaway