i have had my MCS running strong for a few weeks. about 2 nights ago i was driving on the freeway and was speeding up when i lost all power. i went into super limp mode. i thought i blow my head a first, but after restarting and reading on nam i found it was just the minis really harsh limp mode. i got the code checked and it was p0301, cylinder 1 misfire. it runs fine now but were should i start? plugs, cylinder compression?

 

Most certainly not saying this is the cause but those densos and malfunctioning cars seem to be popping up on a regular basis, I'd check those first.

 

The only time my car has made the code of a misfire was when my spark plug wires were grounding on my intercooler. The wires were rubbing on the intercooler.

 

Misfires can be caused by many things. Even a loose connection. FWIW, the P0301 code was seen by the car multiple times to cause it to go into limp mode. The first time it is thrown, it goes into pending status, which you can read with an ODBII scanner. The next time the car sees the code, it then throws your car into limp mode and lights the CEL.

Here's the order I would go thru to troubleshoot the issue. I start with the freebies and move up thru the ones that will cost ya.

1) Remove and reinstall the plug wire...checking for "worn" spots on the coil's post. Try running the car and see if the code is thrown.

2) Swap the #1 and #2 fuel injectors, run the car, and see if the code becomes a P0302. If so, then it's a bad injector causing the cylinder to run too lean and misfire.

3) Do a compression check. All four readings should be within 20% of eachother.

4) Remove and inspect the plug checking for damage, and replace. Maybe it'd be easier to replace all four plugs in a preventative maintenance effort. Try running the car.

5) Replace the plug wire(s) ( a new set from the dealership is only $40.00 ). Try running the car.

6) Replace the coil pack (get an aftermarket upgrade one as they are priced lower than buying a stock one from the dealership). Try running the car.

7) Have the dealership diagnose the problem because the things that it might be ( wiring harness, ECU, fuel pressure issue, etc) will be much more of a pain to troubleshoot.

I see you're in Mesa. I'm in PHX. If you need a hand in wrenching on your car, PM me.

 

thx for the posts guys, i will start working on it asap.

 

I have started throwing codes #1 misfire #4misfire multi cylinder misfire. All in the 5,000rpm and up range. Changed wires still there, changed plugs, still there. Changed coil, all better. I have had a scream'in Demon coil on the car for about 25,000 miles put the stock back on.

 

Update: Wrong the coil is fine still throwing 0300 code at 6800 rpm WOT it stumbles starting at 4500 on up throws code at 6500 then goes into limp mode.
Mike