I'm new here and may be asking a question that has already been answered...or is obvious to everyone but me. I have an 89 Toyota pickup (with a stock 88 Toy carb), 4 speed, 22R, and 125,000 miles. A couple weeks ago I added some fuel system cleaner to the gas tank and everything was running fine. When I was down to less than 1/4 tank of gas, it started running really rough, especially at or near idle. Appears to be running very rich...you can really smell the fumes. But once the engine has warmed up and been driven about 5-10 miles at 40+ mph, it returns to running smooth. If it sits for a couple hours, it's back to running rich and a very rough idle...until it's warmed up. I just barely passed the emissions test by first driving around for about 10 miles until the engine warmed up and the idle smoothed out. However, it's putting out a lot more HC than in previous emission tests. It's possible that the fuel system cleaner freed some crud up in the gas tank which messed up the carb. But I'd think that would affect it all the time, not just when the engine hasn't been run much. I've already replaced the fuel filter. Guess it's time to rebuild the carb. Any thoughts on what I should look for? Thanks.
start with plugs.. tends to foul plugs with that stuff... it works! but plan on changing plugs after good luck hope it helps
Thanks Dux...already replaced the plugs. The old ones were shot, gap looked to be about twice what it should have been. But the new plugs didn't help and fouled up quickly with lots of carbon. Although, after running the truck until the idle was smooth, I checked the plugs again and a lot of the carbon build up was gone.
plugs Sounds like your fuel cleaner probably sent some dirty fuel to your carb. Was there a bunch of crap in your old filter. Get one of those glass filters so you can see whats in there. Try draining out your tank. I agree with dux check your plugs. Sounds like a plug might not be firing.
Check you choke, if its only when its running from cold and fine when at operating temp then more than likely its running too rich while your choke is on.
