1997 Z-71 Vortec Fuel issues PLEASE HELP
 

When i am pulling any weight other than the weight of my truck sometimes (and i mean only sometimes) i lose all power when i push on gas. when i let off gas just a bit i get some power until eventually i completely run out of power. If i pull over shut it off and let it sit for 5 minutes or so i start it up and take off with full power just to have it happen few miles down the road.Her is a list of money iu have put into it the last few years

Fuel Pump 20,000 miles ago (4 in last 5 years)
Intake manifold 3,000 miles ago
Fuel Filter 3,000 miles ago
Brand new tranny 75,000 miles ago


I have benn told it could be an injector issue, Throttle Positioning Switch, PLEASE HELP

could be an injector or TPS....but my gut tells me its the tranny getting hot....my 97 burban did the same thing a few weeks ago untill it finnally just puked all the fluid all over the highway.....a bad TPS or injector SHOULD throw a code but the tranny getting hot and going into "limp" mode will not throw a code (atleast not on the SES light) I would recomend visiting a tranny shop

would a hot tranny flip the Service Engine Light on? and before my last trip i had the tranny serviced with new filter new oil and they said everything seems to look great?????????? I am pulling in 3rd gear not overdrive. if it is a hot tranny what needs to be done to it to fix the problem? Thank you so much for your help

Here is a way to check your TPS. It will also show you on other videos how to check your MAF sensor. Start with those. The MAP, MAF, TPS, and IAC all work together. When one starts to go out, it can affect another. When my MAF sensor went out, it also took my TPS out too. But it never threw a code. I just couldn't start it like normal. I had to full throttle to start it then it ran rich and idled at 2000 rpm. So start testing sensors, then test fuel pressure.

I really appreciate the help and sorry to bug ya so much but goin on a long trip pullin my trailer next week and gota fix this prob.I took it to a guy who seems to know alot about chevys and the computer said it had MULTIPLE MISFIRES?? he says that really doesnt help him solve the problem?? bout a month ago i gave it a tune up plugs, cap,rotor but i didnt change the wires, could that be the problem??? although it was doing it before i tuned it up also. the other day it was laggin around town with no load behind it. first time it had done that. Now this is what blows my mind..... i was pedal to the floor the engine was revving up but i was going nowhere then i heard 1 loud CLANK so i let off the gas and never heard that noise again. Again i really appreciate the help don't know much about this stuff but really want to learn. Thank you

When my TPS went out, the transmission shifted wierd. Of course lack of power, it would hold the gears long then short. When I first got the truck, I descreened my MAF sensor to get more performance. Well it did perform better, but after a few days, my transmission started slippin. Within 24 hours it was gettin worse and worse. I would push the pedal and it would go a little, then bang and rpms would go up. Eventually it burned up the tranny. The only way to make sure ur self about the transmission is to drop the pan and look for metal shavings at the bottom of the pan and whatever fluid you drain from it before dropping it. Do that first to save you time before tryin to assume its the ignition on the motor or something else. A quick way to check your MAF sensor is to start the truck, pop the hood, and tap the sensor with a screwdriver or something. Tap dont bang. If you notice an idle change up or down, the sensor is bad. That sensor has a lot to do with how your engine performs and a big part in feeding data to the computer for transmission shifts. It just doesn't measure how much air is pulled into the motor, but it determines the load on the engine. As well as your other sensors.

The TPS is a good place to start..........If the TPS is bad then you have solved your problem.....have you checked your tranny fluid lately? Whats it look like? Is the truck still "peppy" with out a trailer? My gut still tells me its a tranny issue....but I hope its just a TPS

i just had the tranny serviced new filter new oil and they said so metal in the pan and everything looks great. And NO even without a trailer when i am climbing hills it bogs down and eventually i have no power and have to pull over shut it off for 5 minutes then it will go again for a few miles just to happen again?????

then I would say it is probably your TPS or on an off chance the rod that holds the "butterfly" plate on in the throttle body could be worn

How does it idle? Smooth or a little shaky? When you rev it up hard does it shake or sound likes it missing? Go to your tailpipe while it is idling and see if you notice a strong odor of either rotten eggs or if it is running rich. Running rich will be strong and eventually make your eyes burn. When is the last time you had the fuel filter changed? Check all of these and let us know. I can help you as much as I can but get some more info cuz I know it is bothering you bad for it to run like that. It would me!!

Thanks again for all ur help. My mechanic took it for a spin yesterday after changing the wires and also had a fuel pressure gauge hooked up. well at the top of a steep hill it did it again. he said the fuel pressure was good stayted around 40 to 50 the whole time so he ruled out fuel.he said it was not shifting right and at the right monents. he had a TPS from an old distributor laying around so he swapped them out also cleaned the MAF. I am going for a long trip tomorrow with my trailer so WISH ME LUCK and i will post my results when i return.

So here is a update on my POS. It is getting worse and worse can barely get going 60 on freeway takes about 5 miles to do so. SO i broke down and finally took it to the Chevrolet dealer here in town and they diagnosed it as a FUEL PUMP going bad???? New one year and a half ago and i thought if fuel pumps went bad they just went bad not slowly get worse and worse??????? Another question i have is Has anyone ever heard of buying a faulty fuel pump and going bad really fast? Thank you for all your help

Yeah some pumps will go bad pretty quick. They're electronic, no telling how long they will last. But I'm scratching my head as to them diagnosing it as a fuel pump problem. The symptoms seem to have been goin on for a while. When my pump went out, it felt like I was running out of gas for a few seconds then just stopped. IMO, it sounds like something else.

ruffneck i agree 100% im not sure its the pump either, but they said they were very very confident that was my problem, so i will try it and see ty for your help and advice

If you could find a mechanic with a scanner that will show readings while it is driving, that would narrow down the problem. My fuel pump was 1000 bucks installed!! I would hate for you to spend that much and have the same problem. If that first mechanic showed good PSI on the fuel guage, then the pump is good. Something else is causing it.

Does that year model truck have the Spider fuel innjection setup on it? And isn't that setup a known problem issue?

does anyone hapen to know what the fuel pressure specs. are? he said that it stayed between 40 and 60 and as far as the spider injectors i have no clue

Thats good enough pressure.

here is an update i finally broke down and took it the Chevy dealer. Fuel pump was bad with only 8k on it. then i took it home and SES light came on again so i took it back and they said it was an O2 sensor GOD I HOPE THIS THING IS FIXED $2,000 DOLLARS LATER. thank you all for all your help i so appreciate it

Just to let you know, dont run less than a 1/4 tank of gas. I can hear my pump whining right at a 1/4 tank then I will go fill up and leave the truck running and you can hear the pump whining go away after just a few gallons of gas. I know it makes no sense to not be able to use the whole volume of the gas tank, but little things like this to increase the longevity of the vehicle out weights the inconvenience.