Poor Performance After Fuel Sys/injector Cleaner!

[K9crew]

A few months ago I added a bottle of Valvoline SynPower Complete Fuel System Treatment (see link) to my gas tank.

http://www.valvoline.com/pages/products/pr....asp?product=54

I've used it before as well as SynPower Super Concentrated Fuel Injector Cleaner and I've never experienced any problems. However, since adding VSCFST, my fuel mileage has dropped from an average of 18mpg to about 15mpg. In addition I have a roughness/vibration to the engine at idle that is worse with the A/C on. I recently installed new plugs (Denso Ultra-Fine 0.4mm iridium plugs) in the hope that the situation would improve but no luck. I bought a new fuel filter today but was wondering if any of the fine members here had any thoughts.

:)

[99lsguy]

HI k9!!!!!

Sometimes I wonder if that stuff knocks some crud off just enough to clog an injector or something?

The fuel filter is a good guess. Mine was changed at 60K that is part of regular maintenance schedule. It was dirty.....but normal. The cleaner could have fouled the current old filter in your lexi with more debris.

So, its time anyway to change the fuel filter reqardless of the additive........but the additive could very well have attributed to the problem.

99

[K9crew]

99,

I'm approaching 67k now with the original fuel filter, and like you I wondered if the fuel cleaner caused accumulated matter to block the filter. I borrowed my friend's OBDII reader and no codes showed up so I'm fairly confident that the myriad of O2 sensors are working ok!! If the problem persists after a new air and fuel filter then I may have to take the LS to the local Lexus dealer for some professional diagnostics.

:)

[99lsguy]

Shame on you K9 for letting that fuel filter go 7k over the limit!!!

Seriously, I think it a good fix.........let us know!!!

BTW.......we (family) may be coming to Hawaii in a few weeks!!!! I'll let you know if it's happening!!

[VGR]

Aftermarket cleaners, fluids and filters = risk of damaging the car. OEM products like this one may be boring but eliminate the risk:

http://www.saber.net/~monarch/tbclean.jpg

http://www.saber.net/~monarch/tpcleaners.JPG

http://www.saber.net/~monarch/tbtoothbrush.JPG

[SKperformance]

Try putting another bottle in to clean the rest it may have or get a motorvac to finish the job properly and completly

[vyhanh]

A while back, I put a bottle of fuel injector cleaning into the gas tank. Then the engine started sputtering at idle, acceleration with poor gas mileage. I took the car (91 Galant) to various shops => common advice: replace fuel injector. Just when I decided to do this, the last shop took out one of the injector and put it back => by sheer luck of taking out and reinstalling the (bad/clogged) injector => must have displaced a speck of dirt? => car back to smooth performance !!!!

[mbpgawest]

I agree with skperformance, if you have a reliable shop that you trust with your Lexus, I would have them properly clean the fuel delivery system with a motorvac. This is a professional cleaning machine that will clean all aspects of your fuel system.

Let us know if the fuel fliter did the trick. B)

[93LSOwner]

I purchased BG 44K after I read some posts about it here at LOC. Is that stuff going to clug anything up and how much is to get the motor vac done, just an estimate??

[SKperformance]

about $100

[93LSOwner]

Thanks.

[VMF]

guys, this stuff is not for the tank cleaning, no debrises in the tank this is injector cleaner and it cleans injectors. i think it might be clogged injectors and makes ur car fuel hungry, ECU detects it and tries to put more fuel into the cylinder and that is why you get 15 mpg

[ebridges]

FYI, in my ignorance, I never changed the fuel filter until reading about it on this forum. Never did see it in the manual. However, at 180,000 mi got it changed, but saw no difference on my 96 LS400, purchased new. Anyway, still average about 23 mpg, mostly, but not all, highway miles.

I loved the 96LS so much, I bought a 91 LS400 with 72,000 miles to replace my Accord which died at 230,000 due to a bad radiator :(

I try to use premium, name brand gasoline, to keep down problems with water and injectors however.

Ebridges