Recently picked up a gem, 89 p/u v6 4wd 137k. Ran great for 3 weeks decent mileage good pulling power no major issues. Rained for a couple days and I was hitting a couple puddles along the road when I noticed a small miss at load (low rpm's only) and a little rough at idle. No big deal I figured little water where it shouldnt be. Problem is getting alot worse and has been dry for a week or more now. Truck starts fine no miss at high idle then when it kicks down starts missing doesnt stall just runs rough. As you drive it the problem is hit or miss with no real pattern, may miss bad at pull out push in clutch tach it up a little and then power comes on strong. Do alot of highway driving and when it acts up its as if you are flipping a switch (with throttle in constant position) power comes on and miss goes away. Changed wires, cap, rotor, and fuel filter. Any help would be appreciated no light and o2 sensor under cab is not in pipe I understand this would be your first suggestion however truck was like that when I bought it with no problems other than chek engine light coming on sometimes. Oh yeah ran some lucas cleaner through it no help.
A lot of checking start by inspecting/testing the throttle position and Mass Airflow sensors, EGR, and fuel pressure to include vacuum leaks
October, 31, 2007 AT 8:05 AM
How did I know you were going to say something like that. Thanks for the help I will be excited to get out there and get to the very exciting world of troubleshooting. Thank you for your help I will be sure to get back to you hopefully with good news or with more questions. Thanks again. Coil maybe?
October, 31, 2007 AT 2:29 PM
Coil maybe-but won't hurt to check the primary and secondary resistances in it and also a book if possible. This one might turn into a nightmare.
Get the world of troubleshooting going and report back your findings so that we can continue to the next phase.
November, 5, 2007 AT 8:41 PM
I have the same problem with my 92 v6 3.O. Exact same problem so lets help eachother out! I just had my heads taken off all new valves and no help. New gasket set new idler tensioner assy. New timing belt repaired wires at coil and still. Same problem. I will be checking talking to a mechanic tonight and I will try and post if anything else comes up. Thanks!
November, 6, 2007 AT 9:54 AM
Good news and bad news, good first changed the plugs and truck has been running fine ever since. Bad news, idle gets rough still here and there think it is just a temporary fix. Old plugs looked normal, very worn but nothing out of ordinary. Sorry I cant provide more info but I figure I will just run it till it starts again and then start the hunt again.
November, 6, 2007 AT 11:01 PM
I talked to a head mechanic at 5 star toyota and he drove it and everything. I have changed plugs many times and it is just a temp fix. What it is I think is the injectors or the EGR. Im pretty sure that it is the EGR. He told me that if it is doing it bad then I should unplug the egr and stick a cap in it and see if it runs better. So thats what ill do and ill get back o here. I am also going to ask another great mechaninc if I have time.