1994 Toyota pickup 4X4 22re 5 speed manual

I seem to have a firing problem that no one can figure out. when I start the truck cold it idles and runs perfect, no misses or spitting and sputtering. After driving it and warming it up I kill the engine. upon starting it back it idles very rough, rpm dropping to around 500. upon take off it spits and sputters and sometimes blows back through the air breather housing. once I pick up speed, third gear, it smoothes out. it does this every time I kill it after it warms up.

I have replaced plugs, wires, dist cap and rotor, pick up coil, and attempted to set the timing. upon putting the timing light on it and crossing the termimals, when set on 5 the engine idles way too slow, when idled up to a suitable rpm the timing mark is way off the dial.

any suggestions????

 

Anybody????

 

Your cold start inject may be getting stuck open. Could also be a failed temp sensor telling the ecu the engine is cold but its really hot instead. It would start running better after you drive it because the o2 sensor will adjust the fuel trim.

 

Have you checked for codes? Is your check engine light on? If not, is it burned out (i.e. does it light up when you first turn the key on)?

 

I suggest cleaning the intake, worked with mine.

 

Some of it does sound like timing. Adjust valves ( I retorque my headbolts everytime I have the cover off) make sure terminals are jumped and light is flashing all 1's if no other codes, and the other steps needed in setting the timing that I cant recall right off.

I would raise the front end as high as I could with radiator cap off and let it idle for about 15 minutes to let any air escape the system. Sometimes you see referred to as Burping the system on here.

How is the EGR system? It can get quite dirty. Clean all of the ports to the Plenum as most likely they will be clogged with carbon. Check for any vacuum leaks.

 

How long ago did this start??

Did it just get worse a little at a time or all at once??

Once started it runs and drives fine no matter how far you drive till you turn off the engine.

upon starting it runs poorly once you get into 3rd gear it smooths out??

Then it runs fine till you shut the engine off??****

or does it start running poor when the rpm drops to idle again?? ***

 

Have you tried just setting the idle speed? http://personal.utulsa.edu/~nathan-b...nce/2maint.pdf All of the other suggestions you've received could be the cause of your problem, but if you already know the timing isn't set correctly you could waste a lot of time elsewhere.

While you're in there, check all the parts of the throttle cable and the throttle plate throw. The set-screws setting the position of the throttle plate (e.g, on the damper) shouldn't cause an idle problem, but if something is obviously bent/broken/screw missing it can't help.

 

Idle Air Control Valve- it's stuck partially open, closer to 'closed' than fully 'open', and coolant isn't flowing within it... I think.

Then engine has been tuned- timing, idle speed, et cetera, with it that way and as such the ECU can't compensate properly.

When warm, the ECU want's to enrich the mixture, but that's not what the engine needs when warm.