Okay so im stumped on this one. 1999 Lx Sedan 5 speed, 196k miles, just did a tune up on it, it was running good for the first couple days but now its like this damn thing is in limp mode or something. no power what so ever, and the damn thing is cutting out after i get past 45k rpms. read the codes on it and it came up with p0420, and it had about 6 or so other codes but they were just straight 0's, wouldnt tell me what they were. thinking it could be a clogged cat maybe? its got a loud pipe on it and all you can hear is engine, almost like nothings coming out of the exhaust but it is. tried repacing the fuel filter, changing the oil when it didnt really need to be, ran a can of sea foam through it, some 93 octane gas and some injector cleaner and still have nothing. anybody got any ideas?

 

List what your tune up entailed.
(Note: the tune up might not have anything to do with your car in limp mode)

Lookup all the codes and see if they point to something specific.

what would suddenly clog up the catalytic converter?
(the only reason I replaced the cat on my 91 CRX Si was the NOx level got too high to pass California smog test, no EGR system on the car to lower NOx)
Clogged air filter (or something in the tube before the air filter?)

Look for disconnected wires, vacuum hoses (cracked vacuum hoses too).
Check all the grounds on the car are clean and tight (negative battery terminal, transmission, valve cover, thermostat housing; Note: the thermostat housing ground is the main ground for the ECU)

take care,
ChrisS

 

tune up included rotor button, distributor cap, plugs, wires, an oil change, and new air filter. the only codes the reader would read was the p0420. there was a couple others but they were all 0000000, would read them. and im not sure if anything would suddenly clog my converter, unless the tune up was making it run richer because it already burns a little bit of oil. (1-2 quarts a week) everything else seems to check out alright, no damaged/disconnected wires, hoses all seems okay at visual inspection, i can check to see if the grounds are good but i havent been turning wrenches on it lately so i wouldnt think they would just come loose. thanks for the ideas, i appreciate it

 

What does the p0420 code mean?
(Catalyst below threshold)
Look at the wiring to downstream O2 sensor, possible bad O2 sensor, or the catalytic converter isn't working like it should be. Also, possible exhaust leak upstream from catalytic converter.

What do the spark plugs look like? (Oil fouled, carbon fouled, or expected light tan)

Is your engine burning or leaking oil? (1 to 2 quarts a week isn't "a little bit")

Take care,
ChrisS