Something odd is up

[white7wolf]

Hey all so something odd is up with my truck. If I get on the gas it accelerates kinda slow and then when it gets to 35mph it stop accelerating and the engine RPMS are up at like 4,000. 35 mph is about as fast I usually drive anyways (I only do around town driving) so I'm not sure if it will go faster if I ease it up.
Truck is a 98 tahoe ls with 238,000 miles. The fuel pump is on its last leg and needs replacing, my father in law thinks it might be the pump. Thoughts? Ideas? Tests I can do?

Thanks
Russ

 

[Mechahead]

Sounds like a bad pump(fuel pressure test) or a blocked cat(backpressure test). An easy way to check for a blocked cat is to take an upstream O2 sensor out and see if it runs any better. Its rather crude and CAN be dangerous, but it will give you an idea of whats up.

 

[OR VietVet]

X2.

---------- Post added at 08:02 PM ---------- Previous post was at 07:59 PM ----------

If after you test for fuel pressure and find that it is too low and you change the pump make sure you do the fuel filter at the same time. You could even try the filter first but have never heard of same type of problem just because of a bad filter.

 

[ccapehartusarmyINF.(ret)]

sounds kinda like the PCM is in Limp Home Mode

 

[white7wolf]

Well my catalytic converters have been on there way out (they've been loud from the ceramic vibrating in the bottom for a few months now) so it could be a 1-2 combo of bad cats and bad fuel pump.

 

[OR VietVet]

If you know the cats are going out anyways I would do those first and see if all is fixed after that. May not need fuel pump. No check engine lights?

 

[white7wolf]

Check engine is on due to the 02 sensors and cats not playing nicely. I also had some codes due to random misfires.

 

[HUMBL57]

How's the trans fluid look? Seems like a lot of miles if it's original trans. Are you sure it's not trans slipping?