QuestionQUESTION: Hi Roland!
My question is similar to one you answered for Gerald. My 1999 Nissan Quest runs fine when it is cold, but when the engine gets hot, say after 45 minutes ove driving or idling, it stumbles terribly when I try to accelerate. Like gerald, it stays below 2000 rpm. When I finally am able work the accelerator by releasing and increasing gas to increase speed to like 45 or 50mph, it runs smoother, but I still feel it stumble occassionally. Also when I am sitting at a stop light, I will feel it shake peroidically, but I do not stall. Did Gerald ever determine if it was a bad coolant temperature sensor like you suggested?
A month prior to this happening, I was sitting in stop and go traffic for about an hour when my temperature guage indicated I was overheating. I pulled over and let it cool off. But I noticed my coolant resevoir was full. Could this be related to the coolant temp sensor? MY thermostadt appears to be working okay. I feel radiator end of the upper radiator hose when the car is hot and it is hot, so I feel the coolant is circulating.
Thanks for your help! -Hank
ANSWER: Hi Hank,
I would suggest that you try to do a fault code readout of the engine computer. Check with the Autozone parts store if there is one near you and see if they are still doing it without cost. If not, then get it read out at an independent shop. Ask for the code numbers, what they means, and what they recommend to do, and for how much. Let me know if it doesn't seem reasonable. I can't tell you whether Gerald's problem was the coolant sensor without knowing the date of the original question for a handle on a search of my archive.
Roland
---------- FOLLOW-UP ----------
QUESTION: Hi Roland! I took the vehicle to Nissan for an engine diagnostic. The mechanic at the Nissan dealership says I have a bad distributor, failing due to excessive heat. I have take off the rotor and cover and looked for signs of oil in the optical sensor, but did not see any signs of oil. I'm not sure I trust the mechanic who also recommended a transmission flush (which I hear will do more harm than good on a vehicle with 183,000 miles). He also said I needed a new fuel filter and air filter, both of which I have recently changed out. So I am in need of second opinion of a distributor going bad. Again, the vehicle does not stall. It just stumbles badly on acceleration and sometimes even when I am going 50mph. The diagnostic code showed a knock-sensor, but the mechanic said that code is misleading at times and my knock sensor was probably okay. Please help! Thx! -Hank
AnswerHi Hank,
I don't know the price of a new/rebuilt distributor for the Nissan but if it is like the 2.5L Mitsubishi used by Chrysler it is $1,000/300, very approximately. I would believe the readout of the fault codes which do have one for the knock sensor and for the camshaft (distributor) sensor. If the only one so far was for the knock, then I would replace the knock as that one would be involved in missing during acceleration which is when knocking is the issue. The knock sensor is much less expensive than a distributor. The camshaft sensor in the distributor can be flaky as it gets warmed up when it is at the end of it life, but I would want to see a fault code for that before I took his word for it, given the price.
You can probably replace the knock sensor yourself as it simply bolts to the block.
So take your time and do what is the most reasonable based on the codes and your instincts.
Roland
Hi Hank,
I received the following suggestion from another Nissan owner:
I had the same problem with my 97 Nissan Quest with 180,000 miles. Check the rubber tubing that runs from the thermostat housing that supplies coolant to the metal line which runs to the front of the throttle body. Mine was leaking anti-freeze down into the # 1 spark plug hole causing it to short. Since this only flows after the engine is warm, it could be that you have the same problem.
Roland
