Q: What else do i need to check or what could cause my SUV to do this. TPS replaced 2 yr ago p0171 p0174 were detected 4 months ago

asked by on January 28, 2018

I started my SUV for a third time today and started to notice a vibration & rough erratic idle as well as a change in the exhaust sound thought maybe it would go away as i drove down the road but it didn't. I pulled over and checked the PCV hose and put it back on which fixed the erratic idle. I had to pump the gas pedal to start it and when I reversed it hesitated and bucked then I started going forward it hesitated and bucked hard got upto 20MPH it bucked still I stopped put gas and a name brand fuel injector cleaner in the tank thinking the gas gauge wasnt working but the problem remained I secured the gas cap and headed home. Once I got it home i unplugged and cleaned the mass MAFS while it was unplugged the engine started to run slightly better but the exhaust sound didnt change. Plugged the MAFS in and checked the air filter but it was fine. Then checked the oil and coolant and both were normal checked my 2yr old spark plugs/wires but not spark yet bc i smelled gas in engine bay

My car has 200000 miles.
My car has an automatic transmission.

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Inasmuch as lean codes were set earlier (P0171, P0174) you may have clogged injectors. Fuel trim should be looked at with a real time scanner. If fuel trim is high positive, that would be an indirect indication of clogged injectors. In any event, with 200,000 miles on the engine, the injectors should be removed from the fuel rail for maintenance and sent to a lab such as Mr. Injector for ultrasonic cleaning, testing, and replacement of the miniature internal filter baskets in each injector (these filters can’t possibly be cleaned on the vehicle and that is why on car injector cleaning is really not effective or recommended). If servicing the injectors, which again should be done anyway with this much mileage, does not resolve the rough operation, the recommended service to request is a rough idle diagnostic. Injector service can also be performed by YourMechanic via that same diagnostic service. If you have further questions or concerns, do not hesitate to re-contact YourMechanic as we are always here to help you.

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