1998 Lumina Fuel Injector Trouble

[lkfw]

Help. I have just had lot$$$ of work down on my car which otherwise ran fine without a monthly payment - specifically after getting the Service Engine light the first time I had the fuel system cleaned and the PCV valve replaced. When the light came on within about 10 days I took it back and had a new fuel pump and module installed (with apparently a check of the fuel tank at that time) in less then a week the light was on again and it was running very poorly. When I returned to the mechanic he did as much as he could - a new fuel system clean and diagnostics which showed that the no. 3 cylinder was the problem and sent me to the dealer. The dealer replaced the no. 3 fuel injector and said it had been clogged with some sludge. Literally, before I drove it out of the dealer it started running rough and the service engine light came on. Now 5 and 6 are apparently clogged. Now neither the original mechanic nor the dealer have a clue about what this problem could be. The dealer wants to nickel and dime into searching for the problem. Does anyone have an idea what this could be? Shouldn't my new system be preventing this kind of "sludge" getting to my injectors. Thanks for listening.

[maxwedge]

Welcome to AF. First of all if in fact the injectors are getting clogged somehow, this could have been an ongoing issue, was the tank dirty when the fp was replaced, was the fuel filter contaminated, is the contamination visible on the old injector? They can be pulled out and sent out for a professional clean out or an inline dedicated injector cleaning could be done before categorically replacing all of them. Possible someone " dropped" something in your tank?

[lkfw]

Thanks for your comments. I have now taken it back to the first mechanic. Who is convinced that it is not the tank - although he did not verify that he cleaned it - he did drop it down when replacing the fuel pump. He suspects it is the fuel filter - which I, as a total novice, feel should have been replaced with the rest of the system.

[maxwedge]

Nuts not to replace the ff you are right, when doing the fp, but if anything is getting past it into the injectors then there is stuff in the tank also, got to start at the source.