Q: On 2nd remanufactured Mass Air Flow sensor, & it still runs better with it disconnected. Any ideas? 1001 Dodge Colt

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about 4500 miles ago, I changed oil adjusted valves, changed spark plugs & wires. All part of routine maintenance . 500 miles later I lost my cold start, & had to give it gas to start. Slight pressure on accelerator. Then about 1000 miles later the car began to spit & spudder under acceleration, & while trying to maintain 55mph. I also noticed that it would pop & rumble during deceleration. I disconnected the MAF and the spitting & spuddering went away except for under hard acceleration, & still no cold start. The deceleration issues disappeared as well. I've tried 2 different MAF sensors, both remanufactured & from the same place, and my cold start works again & no issues with deceleration. But it spits & spudders under mild-heavy acceleration or even trying to climb hills, or maintain 55 mph. It is just like its running out of gas or has water in gas. Neither one of these is the case. I disconnect MAF, I'm back to the no cold start, low idle speed, and stumbling under heavy accel.

My car has 252000 miles.
My car has an automatic transmission.

Hi - I would first check for problem codes (even though you are pre-OBD II), diagnostic codes can be very useful in cases like this. It sounds like you have a fuel supply issue - low fuel pressure, leaking/clogged injectors, clogged fuel filter, weak fuel pump, etc. I would check fuel pressure while running if possible, especially running up hills - high load. For diagnostic assistance, I would recommend a fuel system inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.

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Hi there. From what you are explaining it sounds like you have an issue with the valve adjustment. If the valves were not adjusted properly then the valves will not open and close properly. This will also affect the operation of the air flow sensor as the valves will affect the air flow. It can also be a circuit issue but most of the time it is the valve adjustment. I would check the valve adjustment again and do a compression test to see what is going on within the engine. If you need to have this running condition checked, consider YourMechanic, as a certified mechanic can come to you to [diagnose why the engine is misfiring] https://www.yourmechanic.com/services/engine-is-misfiring-inspection

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