I've been chasing a cold start rough running problem - tune up, new EGR, CTS, coil, etc - and while it's been getting progressivley better - it still isn't fixed entirely.

So today I decide to check the "spray pattern" of my TBI injectors - knowing nothing more than there should be a cone pattern.

At idle, both are spraying a cone but the drivers side injector also has fuel dripping from the tip, in the midst of the cone pattern. The one side of the cone pattern looks a little less fine and even than the balance.

By moving the throttle, and burping it to WOT, I cease to be able to see the drops anymore, but as soon as it's back close to idle, there it is again, drip drip drip.

I realize this isn't normal - but could it be a problem?

Can I fix that - or do I have to replace the injector? If I am to clean it, how do you clean a TBI injector - there's no rail to plug into - do I try and dump crap in the tank and plug my filter up?

Any insight would sure be appreciated!

I saw one that was doing that. Ran some cleaner through, pattern came back to normal, and the problem (rough idle) was still there, just as noticable as ever.

Have you ever used a cleaner in the gas tank before? Do you use ethanol? If you use ethanol regularly, your fuel system will have little to no contamination in it, so a cleaner shouldn't clog the filter. Even regular gasoline has many more cleaners in it, so it's probably not too bad.

If I were you, I'd go buy a bottle of Sea Foam and a fuel filter. Dump the bottle in and drive it. If you notice your top speed dropping, change the filter as soon as possible.

I
Have you ever used a cleaner in the gas tank before? Do you use ethanol? If you use ethanol regularly, your fuel system will have little to no contamination in it, so a cleaner shouldn't clog the filter. Even regular gasoline has many more cleaners in it, so it's probably not too bad.


We just got the truck - I don't believe the previous owner used ethanol. I have some "penzoil" injector cleaner in a tank right now - I guess I'll wait and see what happens.

Thanks

Have someone turn the key on while watching the injector that is dripping. The fuel pump will run pressurizing the injectors. If the suspect injector drips. replace it. If not then run some injector cleaner thru the tank. You cold also try running a quart of diesel per 10 gallons of gas in your tank. This will clean the injectors good and the valves. Will even boost mileage.

This happened to me as well. I had the drip on one of the injectors. It caused me to have very poor accleration, so I replaced it and it has been perfect ever since. Pretty easy job and cost about $100.