whenever I accelerate in first gear it holds it for a couple seconds with higher rpms before up shifting. I already changed the spark plugs and cables. my truck shakes when I step on it but only in first gear, after that I have no issue. I scanned it and only shows me code p0300. random misfire on one or multiple cylinders. I cleaned out the throttle body and still nothing. that's the only code I get. another problem is the oil temperature needle is stuck at 80. do I need to change the oil sending unit sensor? please and thank you for your time to reply.
My car has 190600 miles.
My car has an automatic transmission.
Hi there. From the description your vehicle only shakes in first gear, with delayed upshift seems unusual. Assuming the P0300 code is continuing to return, it leads me to believe you may have a fuel delivery issue. Low fuel pressure could be a faulty fuel pump. It could also, be a leaking fuel pressure regulator. This may be why you only feel the problem in first gear and the fuel pressure regulator not leaking bad enough to feel it in higher gears.
The oil pressure gauge stuck at 80psi all of the time is most likely the gauge at fault. This is common with GM vehicles. If the gauge is only stuck with the vehicle on, the oil pressure sending unit could be at fault. If you need to have this taken car of, a certified professional from YourMechanic can come to your car's location to diagnose the unresponsive throttle and advise you on the best actions.
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