please help!! my tacoma is running rough until ab 2000 rpm

Does anyone have any ideas on what I can try to do to fix this problem? I just replaced the plugs wires and temp sensor and its still running rough. Will idle at about 200 rpm for ab 10 sec before it knocks off. It is throwing no trouble codes so I really don't know where to begin. I'm pretty mechanically inclined but this one has got me and a couple other mechanic friends stumped so any tips would be greatly appreciated.

 

Whens the last time the MAF was cleaned ?

 

Vacuum leak?

 

I cleaned the mafs when I put all the other parts on. And if it is a vacuum leak I haven't found it. I've looked everywhere on top bottom everything and haven't found a loose or cracked hose.

 

Check the EGR valve isn't stuck open or closed.

 

Alright finally got the rough idle out but now it won't idle at all. I have a few vacuum lines to check. Thanks guys for the ideas. And btw it ended up being some crossed up plug wires. I bought the truck in the middle of someone working on it and just kinda took over cause the work involved was too overwhelming for them. I've swapped an 03 cab to a 99 frame along with all the interior too. Ill post some pics on my profile if ud like to see em. Still not completely finished tho. I'd really like to know if I can put the 03 front end on this truck cause I already have a radiator support for an 01 to 04. If anyone knows I would greatly appreciate it.

 

Should be good as long as you have the correct core support.

 

Well the Support is for an 01-04 and I have the fenders and frame of a 99 but a 2003 cab. I got a mess lol sounds like that old Johnny cash song ab his caddilac. But I'm slowly getting it together.

 

I also checked all my vacuum lines today and there were none loose so I switched the plug wires back the way they were and there was no change. When I push the pedal to rev it up it almost sounds like its hitting the rev limiter at about 4200. I'm thinking maybe the throttle position sensor?

 

Hell I don't know, could be I guess.. Fuck all this electronic this & that, I long for the day of points/condensers & ballast resistors....

 

I'd honestly rather deal with an electrical system. I've also been an electrician for 6 years too so it comes easy to me but can still be tedious.

 

Any news on your troubles? I am experiencing something similar. Rough idle, especially in neutral. Then, if I am between 50-65 mph, in overdrive and under 2000 rpm, I get some rough engine jumping. Feels misfireish. I just replaced the spark plugs and air filter. Wondering if i need to replace the spark plug wires and the coils. I did notice a little bit of rust in the middle coil. Not sure if it would help or not. Any thoughts?

 

I still haven't found a solution for my problems but I think they go a little deeper than what u are experiencing. If u take a wire brush to them and put some electric grease on it and it doesn't change then u could have a broken or broken down wire or a coil isn't firing properly. If the grease didn't fix it I'd try wires and if that doesnt try a coil. Is it throwing any codes?

 

Did it start running this way immediately after you did the plugs and wires? Did you use twin ground electrode plugs? Are you sure you have the wires running to the correct cylinders? Did you knock a vacuum line loose while changing wires? If you switched the wires around and there was no change maybe it's related to them..