My 2004 Chrysler Pacifica has been lurching at low speeds. My mechanic replaced the MAP sensor and mentioned that there is a lot of carbon buildup in the engine. The replacement of the MAP sensor has not improved the performance. They also did a top engine cleanout, which I’m assuming is the method of injecting Seafoam through the vacuum and into the engine? When none of this worked, they suggested that I run a few tanks of premium gasoline through the engine with a few cans of Seafoam included. Is this stuff safe to use in my engine? I’ve seen a few comments out there that if strong agents are added to break up carbon, that large pieces could break free, but cause other damage to the engine if lodged in the wrong place. Is this something I should worry about, or is this even something that could help resolve my problem?
It depends on who you talk to.
Many will say that Seafoam is a gift from the gods while others consider it the work of the devil.
Personally I don’t think adding it to your fuel tank according to the directions on the can will hurt anything, but I don’t think it’s going to solve your problem either. Of course Seafoam is relatively inexpensive so…
Sea Foam has never caused any noticeable damage of any kind when added to the fuel or poured through the throttle here. It is one of several products which do seem to clean injectors and intake ports. It might be worthwhile to try the product before jumping into deeper ($) efforts… Has the fuel pressure been tested while driving?
SeaFoam is a great product and will work fine on a problem that actually needs something like this. SF should not be considered a miracle in a can that solves every problem.
SF and/or any carbon that comes loose will hurt nothing.
Has anyone actually scanned this vehicle for codes or has this all been wild guessing?
There are a number of things that could cause low speed lurching but not enough info is known to even make a guess. Codes first and go from there.
With a code reader, and engine analyzer, and a vacuum gage your problem can be diagnosed and solved properly. A can of Seafoam contains none of these things.
You need a better shop. Your mechanic is guessing. Skip the Seafoam and find a good owner-operated shop run by a good diagnostician rather than a parts changer.
Note: there are a number of possibilities including BUT NOT LIMITED TO weak ignition performance (a bad coil perhaps) and a bad injector.
Seafoam is unlikely to damage anything, but I doubt it will cure your problems.
Just exactly did the mechanic determine there was “a lot of carbon buildup in the engine?” Since neither he nor you can see inside the engine I’d like to know how he came to this diagnosis.
Suggesting additives as a cure for mechanical problems seems like a cop-out to me. I suggest talking to another mechanic.
Safe as you can get. It says, pure petroleum product on the label. To me it means that there aren’t any sea parts in it. I used it in my truck and I think it helped. I even think my fuel economy improved but I forgot what type of driving I did.
Thanks for the responses. To elaborate a bit more, I offer the following. I don’t have a longstanding relationship with this mechanic, as we just moved to the area and only have been there a few times for oil changes, etc. When the car was taken in, there were no codes found. However, since that time a code of P0406 would show up one time, then be gone the next. It has not shown up again in the last week. According to this mechanic, he believes that the carbon buildup can sometimes make the egr valve stick and could cause this code to appear. As I mentioned, this code is no longer showing up now. Regarding how he knows there’s carbon buildup, I guess I can’t be totally sure. He explained it to me at the time but not being an expert, I didn’t understand all of it. He had indicated that when they removed the MAP sensor, etc there seemed to be a buildup in some of the lines? In any case, it sounds like I should maybe take it to another mechanic for a second opinion or to a dealership? I’m currently not driving this vehicle much and will take awhile to run a couple of tanks of gas through the car and I’m anxious to get a more certain diagnosis.
Aha! Now that we have clearer details, it makes sense.
Yes, P0406 in dicates a problem with the EGR system.
Yes, since EGR systems include a small orafice that passes exhaust fumes into the engine’s air instream, they can get contaminated with carbon from the exhaust. It sometimes doesn’t take much buildup to make the EGR valve sticky.
Yes, a sticky EGR valve can cause lurching at low speeds. It’s function is to allow a bit of exhaust gas into the air instream to displace a bit of oxygen under heavy load and prevent the cylinders from overheating. At low speeds, if it lets exhaust gas into the instream it causes a problem with the fuel/air metering.
Did he try cleaning teh EGR valve?
Knowing these new facts, I’m not sure you need a new shop. Everything makes sense now.
And Seafoam won’t fix that carbon buildup, it has to be removed manually. Seafoam will clean any surface that the fluid can touch; injectors, combustion chambers, valves etc but will do nothing for the crankcase ventilation or EGR system.