Have a 2000 Plymouth neon (4 cyl, 2.0) with loss of power and backfire , car has just been tuned up (plugs, wires, throttle body cleaned, air filter, oil change). Just changed the ignition coil today power is back, but its still backfiring. Any ideas?

Timing belt slipped a tooth, stuck valve, plug wires crossed, or a very lean condition.

I suggest not driving it until the timing belt is inspected or replaced

Tune up due? plugs, wires, cap,rotor, Clean the throttle body/ carb, replace the fuel and air filter. Check for codes.

old post , and great question

the TB is a thing that contains the AIR throttle, the body holds

that TV throttle valve (or some call it a TP throttle plate)

this car has 6 engines, and varies by country. what country>?

what engine? (USA cars have a hood EPA tag, it states the engine)



sure cleaning it can help and for sure with throttle by wire.

the body gets full of EGR/PCV crap. (called GUNK) and if not

removed on high mileage cars, it jams the silly throttle by wire

motor. (and related\'s)

why not scan the PCM and SEE ALL DTC errors.

that be first. !!!



loose power has many causes, up to 50.

why not scan it first, (the CEL lamp to me is useless , unless stuck on)

scan it first.

this engine has many limphome modes (suzuki failsafe)

and will run slow. in limp mode.

scan it.

the TBW , throttle by wire has it\'s own limp mode.

the transmission too, and others.



The TBW has up to 4 TPS sensors. 2 on the foot and 2 in the TB

if ANY of the 4 , do not AGREE, you go to LIMP HOME MODE>

or end up like a Toyota and huge class action lawsuits.



loss of power, not transmission caused, (slips or skips gears)

is engine power loss.

cause by (top ones of 50)

1: never getting a tuneup. and for sure the 60k mile.

2: misfire, caused by 3 major things. ask.

3: flooding.

4: bad spark see #1

5: clogged air filters see #1

6: clogged fuel filter.

7: weak fuel pump.

8: and the big one is loss o f engine compression for huge list of causes.

9: not scanning the PCM and believing what it told you. !!!

The neon does not have a MAF sensor. The intake air temp sensor is located in the air snorkel between the throttle body and the air filter.

I’m happy to assist further over the phone at https://www.6ya.com/expert/jeremy_d728a59f986299fa

The air filter has nothing to do with an codes you get.

The PO505 --IAC (Idle Air Control Valve) should
be on the throttle body near the base.

You can remove & clean it or replace

New spark plugs, oil and oil filter, transmission flush and fill, fuel filter, air filter, coolant flush and fill, clean throttle body plate and bore, clean the MAF sensor, replace any loose or cracked vacuum lines, PCV valve, new air filter, new battery.

99% of the time all you should ever need for a tune up is new spark plugs, and a clean air filter and throttle body. But since your inquiry indicated "major" I gave it more critical thought.

P0302 is miss fire #2 cyl like a bad plug,wire or coil P1684 will set if you have lost battery power or battery has been disconnected the miss fire is why the car is jerking

Tune up is a very vague word. But I would suggest, replacing spark plugs, wires, Clean throttle body, replace air andf fuel filters, check drive belt.

Check fuel pressure when it dies? Or remove air intake hose at throttle body inlet, open throttle slightly,(with key off) and spray wd-40 inside throttle body for a second or 2, then try to start. If it starts for a second or 2 then quits, you have a fuel delivery problem, such as bad fuel pump or plugged fuel filter.

Try cleaning out your intake (get some stp throttle body cleaner) try running some fuel cleaner through you gas tank, check you air filter. maybe you could replace your spark plugs and wires. these are just a couple of things I could think of that could cause it.