MustangMom

Hi! Just swapped out a spent 4.6 for a used one with 24K miles on it. After getting it in, there is a moderate "miss" to the engine. Had a local garage swap them out and they changed plugs and wires, fuel filter and set timing correctly, but still has the miss to the point that the car bounces while idling. Seems like it may be using a tad bit more gas as well. The "Service engine soon" light comes on and blinks, then stays lit for a while, then blinks again. Any suggestions as to what might be going on. Compression checks have been made and all is well in that area. Taking her to the dealer on Tuesday for a "machine" diagnosis. Just wondering if someone could save me some time and money. Thanks!!

GreyStang

Check each plug & find the "dead" dead cylinder(s). Check for spark on those plugs and/or a dud fuel injector?

TwotoneVert

Also take it to Autozone or somewhere that they will pull the codes for free. The blinking check engine light is telling you the code, we need to know what it means.

MustangMom

I'm a bit worried now. I took the car to Autozone and they tested the code. Said there was a misfire on the fourth cylinder. My son bought new spark plugs for it again and the wires had already been checked. Still, no change. The motor only has 24K miles on it. It was taken from a car involved in a front end collision. What is the verdict??? Anyone?

corvetteguy

Maybe change that one wire.

GreyStang

If the compression is good on that cylinder, and you can CONFIRM there is a spark (test for spark with the plug out of the cylinder) then next thing is to check if that cylinders fuel injector might be bad..

TwotoneVert

Like Grey said, you need to check compression on cylinder #4, Autozone will rent you the tool. If you have good compression, then the engine should be fine. If you have spark, then you need to make sure you have fuel, like said above, injector maybe. It could be something simple.

MustangMom

Fuel injector is the next thing we were thinking. Hopefully, that will be the answer. Will let you know how it turns out. Thanks!

GreyStang

Good luck with it. Easiest way to test an injector is to swapp it with another cylinder. If the "other cylinder" now starts acting up you know it's the injector itself, if #4 still is screwing up it may be the wires leading to the #4 injector. Keep testing 1 system at a time & you'll figure it out

MustangMom

It WAS the fuel injector!!! I'm so glad it wasnt a bad motor! Although it did cost 240.00 to fix, it is back to its great self finally. Tried 'er out and am convinced she is better than ever! Cant wait till a warm day to go topless with her. She is a convertible, that is! LOL

thanks for all of your help!!!!!! You are all the greatest!!

Now, I'm looking for some nice wheels, a light bar, and exhaust system. That'll do for now. LOL
MustangMom