Engine is missing

[odormat000]

I was driving home today in my 91 Plymouth Laser RS and suddenly my engine started to miss. It's just a really bad idle and when I give it gas it accelerates very slowly and it tooks several seconds for my boost to increase. I went and bought new plugs and wires and the problem didn't go away. It feels like 1 or 2 pistons are missing. I did a compression check and they all passed. Could it be a bad coil? Or a blown head gasket? Please help!

 

[yesItsdsm]

Check for boost leaks.

 

[odormat000]

I was thinking maybe that but that wouldn't cause it to have a rough start and idle would it?

 

[yesItsdsm]

I was thinking maybe that but that wouldn't cause it to have a rough start and idle would it?

Yes, It would, especially if its a big leak. Also check to make sure you don't have any vacuum leaks while you're at it.

 

[90laserRSfwd]

could, although unlikely. clogged fuel filter or bad injector I think....

 

[yesItsdsm]

could, although unlikely. clogged fuel filter or bad injector I think....

That would cause his motor to miss, but boost wouldn't be affected so much.

 

[eagle_talon90]

If it accelerates slowly when you give it gas, I would check the timing, it could have skipped a tooth or two.

 

[odormat000]

i have confirmed compression and spark on all four cylinders but the number one cylinder stays cool on my exhaust manifold while the other ones are getting very hot. does anyone know how to test an injector? also i don't think it's a boost leak because it still gets up to full boost, just very slowly because a cylinder is missing

 

[delta448]

If you have an infrared thermometer, an easy way to check if it's the plug or plug wire would be to swap the plug wires on number 1 and 4, then see if the temp on number 4 goes cold like 1 did. The DSM ignition is a wasted spark type. Cylinders 1 & 4 fire at the same time and 2 & 3 also fire together, even though only one cylinder is on its compression stroke. However, I doubt it is the coil if both cylinders are not affected. Usually the coil fails completely, not just one side of it, and eliminates 2 cylinders in the process.

My guess is the injector wiring on number 1 or the injector itself.

 

[odormat000]

well it runs like there are two bad cylinders, if another one was to not be working as well would it be number four? making me to believe the coil went bad?

 

[delta448]

Very likely.

The FSM, a Hayne's or a Chilton's manual should contain the testing procedure for the coils, sorry I don't remember it off the top of my head or have one of those handy since I'm at work right now. You'll need a multimeter though.

 

[Freerevving]

damn I thought his was going to be a story about how someone stole your engineWTF

 

[odormat000]

ha ha very clever. And I was going to look how to do that in my manual but i have seemed to have misplaced it somewhere but hopefully soon my baby will come back to me