- This topic has 6 replies, 3 voices, and was last updated 6 years, 6 months ago by
.
-
Topic
-
My 2000 impala with the 3.4l has been jerking and bucking and sometimes stalls when I’m going above 50mph. It’s not an every time thing. And it doesn’t matter if I’m accelerating or going at a constant speed. I replaced the MAF sensor, MAP sensor, Fuel pump, fuel filter, and the TPS, and cleaned the throttle body. I replaced the head gasket about 9 months ago and all fuel injectors and connection looked fine. I did a fuel pressure test and it can back normal. It has all new coils, plugs and wires, tested battery and alternator. Cleaned EGR valve and it’s not throwing any codes. It idles just fine and drives all around town as long as I’m going under 50mph. When I am on high speed and it does stall when I get it pulled over it fires right back up and doesn’t skip a beat. So it doesn’t seem like a crankshaft sensor.
-
Replies
-
A couple of things you can look into.
Check your fuel trims.
Possible faulty O2 sensor
Possible faulty fuel pressure regulator
Possible blockage in the exhaustThe fuel trim is looking normal. And the temp on the Catalytic converter is what is should be. And the O2 sensors are functioning. The voltage on both are what they should be. Nothing out of the ordinary. How would I test fuel pressure regulator. Or is it Just a replace and see kind of part.
I know you checked fuel pressure, but did they/you check fuel volume?
Normally high speed misses (related to fuel) are related to fuel volume issues
I agree with Raistian77
As to the cat, I wasn’t asking about temp reading.
A partial blockage will increase back pressure at higher speeds.I will check that as well. And just another thing. It only does it while driving. I can sit and rev the engine up all day and it won’t, or I can go from a stop and pedal to the metal and it takes off just fine. Wasn’t sure if I mentioned that. Thanks guys for all the ideas.
- You must be logged in to reply to this topic.