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rpmdiag, Tech and Instructor
Category: UK Car
Satisfied Customers: 8151
Experience:  Since 1975
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In a 2004 Forrester 2.0 just bought will 100 mph but when in

Customer Question

In a 2004 Forrester 2.0 just bought will 100 mph but when in traffic as I am now the engine shutters almost ready to stall. It was standing for months before I bought it just drove 300 miles placed ,2 cans RedX injection cleaner problem still exists...ideas?
Submitted: 2 years ago.
Category: UK Car
Expert:  rpmdiag replied 2 years ago.

Hi, I’m Ron and I can help you.
I have been in this business since 1975 and also teach automotive repair. I am confident
we can resolve your problem together. Please understand that I don't know your skill
level. I can't see, smell, hear, or touch the vehicle either, so it may take a few replies to
get to satisfactory results. Please be patient!
I also try to give all of the information you may need, expecting a “positive rating” in
return. I will also continue assisting you after you have rated me, if necessary. If there
is any reason I cannot get a positive rating, please let me know why “in advance”, so I
can go another direction for you. I am sorry you’re having this problem; I’ll help you
through it.

Most cleaners are great for maintenance only. It sounds like the long sit caused a varnish buildup and needs to be flushed from a machine with high power chemicals. The best thing to do when a car is going to be sitting, is to add fuel stabilizer so this doesn't happen again. Thanks, Ron

Customer: replied 2 years ago.
I'm a very smart guy with years of engineering in F1....after 350 miles the car runs like a bear...120 mph no problem...the issue here is shuddering shaking at idle arround 750 rpm...over to to you.
Expert:  rpmdiag replied 2 years ago.

Ok, then check the EGR for being stuck in a semi open position this would cause a lean condition at idle and shuttering like you described. Don't forget to clean the intake and exhaust passages very good. If this is ok, then search out any other potential vacuum leaks such as at the PCV or brake booster. The best way to check for vacuum leaks is with water.

Thanks again, sand please don't forget to rate me:)