03 sonoma 4.3L

[Eric Taliaferro]

i get in my 03 sonoma 4.3L and after 10 minutes of driving my truck slows to 20 mph and will not go any faster even with gas pedal to floor.

i cut it off and let it sit for about 10 to 15 minutes then restart it and it runs fine for about 10 minutes then back to 20 mph, i've changed fuel filter.i changed oxygen sensors, it still does same thing, it idles fine and doesn't stall out just slows to 20 mph,,,, i appriciate any help i can get.

 

2003 gmc sonoma

king cab 4x4

4.3L engine

automatic, 4 door

[davester]

maybe read codes from the computer?  Just because the CEL is off doesn't mean the drivetrain has no problems.

[txab]

Check for codes. Sounds like a fuel pump issue. I had similar, I couldn't go above about 40-45 mph. Swapped pump, all was well. Checking fuel pressure will probably be required at some point, especially when it will only run at 20 mph.

 

Codes first though

[Eric Taliaferro]

i'm getting a P0101 code

[txab]

Have you checked the MAF connections or at least cleaned it with the correct cleaner? A replacement may be in your future

Edited June 2, 2020 by txab

[davester]

Note, if you do get another MAF sensor, I would suggest sticking with an ACDelco one, as they seem to perform better, at least with that generation truck.

 

I know with my truck, when I bought it, it had a bunch of codes, including P0101, I replaced it with a new Airtex?(I think, it's been years) one from NAPA, it seemed to work fine in general, but would sometimes still generate the P0101 code (generally when it was really cold during the winter).  I replaced it with a used ACDelco one from my parts truck, and that one has worked fine and hasn't generated a code since then.

[Niners 365]

I see a lot of great responses to your problem, and I will add my 2 cents. the P0101 for maf sensor was just 1 of my problems with my 2003 Chevy s10 4x4 w 4.3. It spread like a virus once that one hit around 125000. I replaced mine about a year and half ago now. But that is also considered a generic code for all GM vehicles. I cleaned mine with cleaner and a soft brissel brush with no avail. So I replaced it with one off Rock Auto and it works just fine, it is an AC delco Reman. Then my head gasket went out, distributor was bad. and fuel injectors were bad. I am the 3rd person to own the truck, so you can see whay I inherited. After all that had the crank sensor go out. So start with the new maf sensor, but I dont believe its causing your loss of fuel pressure. That sounds more like your pump and sensor is going out. But I have heard of strange things clogging up one end of the fuel filter and folks still had same prob after putting in new fuel pump. So make sure you change out fuel filter as well.

[Matrix6834]

I’m having a similar issue. 03 gmc Sonoma. At lower RPMs feel a little rocking  /shaking then get codes P0300 and P0151. Replaced plugs /wires and o2 sensors. At higher rpms runs smoother but then check engine light comes on flashing. Truck has 248,607, motor has 5,431 on it. I’m lost.