Car rough idle and one intake port running hot 2x as hot as the others
The intake valve on that runner may be bent or stuck open. Have a compression test done on the engine.
Here are the most common causes of idle surge, rough idle esp when cold, other symptoms include stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake
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Problem solved! Did a compression check, and no compression at the hot chamber. I'm assuming a stuck open valve, so off with the heads and to the head shop! Probably won't be lucky enough to be a broken spring?? But if the heads come off, I will replace the injectors and the timing chain assemble. Thanks anyway!
Of Course I did! Took heads off yesterday, and it was a burn valve (stuck open). Never had this happen to me before? Do my own maintenance, use synthetic oil, change oil at 3 to 5 thousand, drive gentley - just puzzling? Thanks for your time!
Just took the heads off. When I opened the valve cover over the hot port, the spring on the lifer was broken. Decided that I had already come this far, I took the heads off, and the valve was stuck open. Will take them to the local head man in town tomorrow, and get the valves reground and reseated as well as all the springs replaced. The pistons and the piston chambers looked fine to me, and I saw no evidence of cracks or leakage (in heads, head gasket, or block), so I stopped there. I have replaced every sensor, but the cam sensor and the coolant sensor. Will do those, as well as the injectors, and o2 sensors, and heater hoses. I'm debating about the timing chains, but they looked good to me (no play or evidence of ware). I will price a kit, and if not too bad I will replace as it has 162,000. Wanted to keep it 2 to 4 more years. Other than this it has been a good vehicle. Probably would have been fine with a spring replacement, but just wanted to make sure that the valve was not burned, and piston was good. Should have it back on the road by next weekend, and with the head rework, and all parts replacements, it will run me about 1K (much better than the shops 4k engine replacement, and the 1K worth of other things they would have have to replace). Thanks for the concern, and thank God for Snapon and MAC tools. All the work went smooth as silk (except for the CAM pulley (need four hands to get it started) and for the garage with a lift that I don't have - I will have as soon as the house is paid for). Regards, Mark
i really appreciate all the info. it sounds like you never even had to come to this site. here's to a smooth install.
sorry to hear that. is that an overhead cam? if you are so inclined, i'd like to know if you find out why it stuck open. good luck!
did you make sure that cylinder was on the compression stroke?
higher combustion temperatures are normally associated with a lean burn condition. more air or less fuel entering the combustion chamber. the fuel injector may be clogged or not opening long enough to provide sufficient fuel or there may be a head or intake manifold leak allowing more air to enter the chamber..
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