New guy needs some help, misfiring

[jurob]

I'm not a mechanic just trying to help a friend with an 01 Corolla. He's din on his luck and can't afford to pay a mechanic to fix it so he's one of my extra cars in hopes that I can get him back on the road reliabily and safely.

Has a check engine light. Runs good if you give it very little gas. Anything over about 1/8 throttle it falls on it's face. If you floor it bogs severely and won't rev or accelerate. 1/8 throttle and below you can drive it, but obviously very slowly. In neutral it will do the same at full throttle and at light throttle revs smooth to about 4k.

2 codes p0300 and p0301, multiple misfire and o2 sensor.

Where I'm at now. Don't think a bad o2 sensor would cause these problems so I will have him replace when he is able.

Was thinking maybe a clogged cat. Removed the upstream o2 so that I could unrestrict the exhaust, no help.

Read about bad or clogged injectors and just put sea foam in the tank and will drive the car more.

Can anybody give me ideas on what other things to check?

[jurob]

I also disconnected mass air meter to see if that eliminated the problem, it didn't.

[pdq]

My bet would be spark plugs or the coil packs. If the spark plugs look okay, you might want to try swapping the coil packs to see if the P0301 code moves to a different cylinder (ie cylinder 4) before buying a new coil pack.

[landphil]

PO301 is #1 misfire, not O2 sensor as you stated unless I'm misunderatanding and it has a total of 3 codes. PO300 is Random/multiple missfire. Start with plugs, not just visual, proper gap is critical too. Then swap coild packs to see if the problem follows the coil pack.

[Diaz984]

definitely check the plugs first but it could also be the maf or tps sensors since you are experiencing the problem when you start to give it gas. if it the maf or tps it can cause it to run lean which can affect certain cylinders more than others and cause them to misfire.

[jurob]

Swapped 1 and 4 coil yesterday, checked plugs and did a quick rinse of the maf......ran much better rechecked codes and now had lean code.

Cleaned maf thoroughly and it runs very good and was able to get him his car back to him.

Tks for all the help!

[briankmizell]

i have a 98 corolla that was acting the same way. it idled good, and reved pretty easy while in nuetral, but but in gear if you barely gave it any gas is would mis and spit and spudder.

Also it sometimes would not start unless you pushed the gas pedal just a tad bit. This seemed odd to me since its not a carbureted engine.

The not starting issue was sporadic and it would start each time you barely gave it some gas.

But last week i pulled it into the garage to repaint the car, Its sat all week and when I try to start it now, it wont start at all.... no matter what I do.

Do you think my coil packs have went out, if so how do I test them?

[fishexpo101]

^^^ Did you pull the plugs to see if you still got fuel (plugs are wet)?

As for coils - you can use a ohmmeter to check the coils - the typical range of valves are listed on this forum, as someone already posted about something like that some time ago.

Same with the plug wires - check them with an ohmmeter to see if any are open - also a good time to check them for physical damage (chewed up insulation, bare spots, etc.)

Having to push in the gas a bit to get it to start does sound a bit odd. Might not be an ignition issue - could be fuel related, either a gummed up throttlebody or clogged or dying fuel pump.

[briankmizell]

Originally Posted by fishexpo101

^^^ Did you pull the plugs to see if you still got fuel (plugs are wet)?

As for coils - you can use a ohmmeter to check the coils - the typical range of valves are listed on this forum, as someone already posted about something like that some time ago.

Same with the plug wires - check them with an ohmmeter to see if any are open - also a good time to check them for physical damage (chewed up insulation, bare spots, etc.)

Having to push in the gas a bit to get it to start does sound a bit odd. Might not be an ignition issue - could be fuel related, either a gummed up throttlebody or clogged or dying fuel pump.

When I pulled the plugs they were coated with oil, not burned on oil fresh oil. The only time the car would smoke was when it was revved hard (say 4700 + rpm's). I cleaned them with laquer thinner.

The batteries are dead in my tester so i couldnt test the plugs or wires.

I pulled one plug wire at a time and put it against the valve cover while cranking, it is getting fire, the spark isnt blue.... it mostly whitish/yellow sometimes orange.

I pulled the quick disconnect line on the fuel and turned the ignition on, I am not getting any fuel.

I am hoping this is a relay (if it has one for the fuel pump) and not the fuel pump its self. Chances are its the fuel pump cause the car has 182,xxx miles on it.

If anyone knows if the 98 corolla has a fuel pump relay, could you inform me of where its located. or better yet a link to an online shop repair manual for the 98 corolla.