QuestionQUESTION: The car is sputtering if I let off gas while driving. If I push down on gas pedal, it will stop. Midas told me it was the head gasket & it would cost $1500. I used Bar's Leaks Head Gasket Fix and it doesn't seem to have fixed it. I don't want to put anymore money in this car, I just want to get by for a few more months. Any ideas? Could it be fuel filter? I just had the timing belt replaced a few weeks ago. I had a tune up in Jan 2008. Also the oil sending unit replaced in Nov2007. It only has 128k miles on it & I was hoping it would last longer
ANSWER: Hi Jennifer,
Are you sure that a head gasket is the problem?: are you loosing coolant on a regular basis? Do you have white smoke out the tail pipe when you start the car from cold (which also smells like antifreeze)? Is the oil milky? Does the engine bubble during warm up? Those would be corroborative of a gasket leak. If not, then not. If so, you could find out which side is leaky and try tightening down the head bolts on that side in case that is the reason for the leak rather than a torn gasket.
Other than that, use the ignition key to get fault codes that the engine computer may have stored in its memory that might tell us something to improve things. Turn the "on-off-on-off-on and leave on, doing that in 5 seconds or less elapsed time. Then watch the check engine light, which remains 'on', to begin to flash, pause, flash, etc. Count the number of flashes before each pause. Then do it again to be sure of an accurate count. The last two sets of counts will be 5 flashes each. Then group the counts in pairs in the order of appearance to form the two-digit fault codes. The last number is always 55 which means 'end of readout'.
Then write back with the results and we'll go from there.
Roland
Hi Roland - I followed your instructions for getting the codes but all it's giving me is the 2 sets of 5 flashes each. One thing I noticed after we put the Head Gasket fix in the radiator was the gas mileage improved. I drove it to Nashville & back (bout 300 mile r/t) & it got about 20-22 mpg and doesn't smell of gas when i first start it. The last 2 weeks it's been getting 10-15 mpg. The idle sounds a little smoother but it's still sputtering when I drive. If I stay on the accelerator and get it over 50-60 mph then it acts like it's running fine. It sputters when I'm under 45mph or so or when I left off the accelerator
Hi Jennifer,
Thank you for the nomination, and the report on the readout of codes. Because you don't have any codes we have to focus on items that might 'fly under the radar' of the self-diagnostic capability of the engine controller.
Let's assume that the ignition system is o.k. and think about mixture. One possibility is that the temp sensor is not accurate but not so bad as to cause a code, and similarly with the manifold absolute pressure sensor, but you would need a voltmeter to access whether whether either of those could be true. So let us sit on those until we 'exhaust' the other possibility and you let me know if you have access to a volt-ohm meter.
I have another idea, one of my favorites when bad idle rears its ugly head. I would take a look at the exhaust gas recirculation valve which is located behind the engine near the air intake throttle valve. It is mounted in a pipe that runs between passenger side exhaust manifold and the air intake manifold. The valve is mounted horizontally and has a valve stem between its round vacuum actuator top and the body of the valve attached to the pipe, inside the flange that connects the two parts. The stem has a slot into which you can insert the tip of a flat-bladed screwdriver so as to lever the stem back and forth against spring action which should move freely and close tightly. If the stem seems to be sticky so that stem doesn't close all the way by spring action, then you can try spraying some penetrating solvent like WD-40 on the valve stem to freeup its motion.
If the valve is sticking slightly ajar it will make for a rough idle and poor acceleration such as you describe because the mixture is too dilute. It is one of the most common causes of this symptom. So see if you can find the valve and check/lubricate the stem. To check it in motion you can rev the engine from idle to 2500 rpm and back to idle and watch to see if the valve stem moves freely in both directions to the extreme open and closed positions. It may be that the interior of the valve is cruddy so that might require that it be unbolted from the pipe where it it attached and cleaned. But chances are good it will only be a sticky stem. Feel free to write back with the results and other questions you might have.
Roland
PS What about the symptoms that I suggested would support the head gasket leak is present?
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QUESTION: Thank you for the tips, I will try them when I get someone to help me again. Sorry I forgot to answer you about the head gasket leak...I did not have any of those symptoms. No smoke or low antifreeze but I did smell gas in the overflow reservoir. I have paid better attention to the symptoms the last couple of days to pass more info on to you. It seems anything under 2000 rpm's is making it shimmy/shake. If I try to lightly accelerate, it shakes the whole car until I get over 2000 rpms...then it smooths out. The speedometer jumps around when I'm driving anywhere from 3-5 mph on either side. The gas mileage is terrible & I smell gas when I first start it up & start driving. (Just in case any of that helps)
AnswerHi Jennifer,
I wonder how things worked out with the engine? You can report back if you like by the 'thank/rate' tab below, without having to wait for me to be 'available' to take a question. While you are there, if my answer was helpful I would appreciate a vote of 'yes' for the 'nomination to be expert of the month'. I am in a close race for that honor so every vote is helful. Thanks in advance.
Hi Jennifer,
Thanks for the further history but nothing jumps out at me beyond my earlier suggestions. Do check the egr valve, and then if that isn't it see if you and your helper can get a volt-ohm meter to do some sensor checking.
Roland
