What's everyone's favorite plugs and wires? NGK on plugs and GM Performance, DUI, Moroso, MSD, etc.?

 

My Vengeance wires and NGK V-Power plugs showed up today. Would have preferred Iridiums over platinum, but it is what it is. Will try to get them installed on Friday. Any recommendations on specific tools required over the average wrench, socket, etc.?

 

Okay, changed out the plugs and wires. What a PITA!! I had half NGK and half other brand plugs. Odd. They were gapped to .085!





It started up and ran smooth at idle. No issues. Then I took it out for a drive. Got on it a bit under 40 MPH, again fine. Hit the highway and the SES light started flashing - misfire. I disconnected the driver side front o2 and did the same. Same issue. Plugged the driver side back in, then unplugged the pass. side. It ran great for a bit 'til I got it about 5 minutes down the highway, then it started doing the SES blink and misfire.

Any other ideas?

 

Drove to my buddies. He is a mechanic for UPS. It was approx. a 35 minute drive. Car was fine for 3 minutes then went to misfire. It mainly misfires above 25 MPH, typically in the higher gears and higher RPMs. On the highway it's almost a constant misfire (CEL blinking) until I drop down below 25 MPH and then eventually it stops blinking, though I still feel the misfire.

Checked the passenger side cat - it's okay. Didn't get a chance to check driver side cat. We did check both cats with my g/f's infrared thermometer. Driver side was 475, passenger side 375. Between the front/back of the cats it was only approx. 40-60* max. Here's where things get odd though...

We figured we would test the injectors, coil packs, etc. While the car was running we pulled one injector (the wiring obviously) at a time. Each injector, when unplugged, caused the motor to drop and run worse than it already was. That was, until we got to cylinder 5. When we pulled the plug on cylinder 5, nothing happened. We swapped coil packs quick to see if it was related to the coil. The problem did not move.

We swapped the #5 injector to a Ford injector that was the same clip/setup, just to see what happened. Started up the car and my CEL turned off. (It's showing a P0420 for the o2, and a random cylinder misfire btw). The problem got worse. We put the stock injector back in to #5. CEL came back on.

Ohmed out the injectors. All were around 13.1, though on cylinder 5 we had a a reading of 14.2 and also 13.2.

I drove to Pep Boys just to get some Sea Foam for S&G's. Left my buddies, drove the 5 minutes there. Car drove like ****. Went inside, no Sea Foam, came out. Started the car and it drove perfect for about 5 minutes. Then back into crap. 10 more minutes and I was at Advance Auto. Went in, got Sea Foam, came back outside. Car drove great for 5 more minutes, then back to crap again.

Bad injector? Something internal? Something else?? I just sold my Jeep and it's too cold for the bike so I NEED to get this car up and running as it's my DD now 'til I pick up a new Jeep. Thanks...

 

Wish i could help!

 

I appreciate that. I'm so sick of this car... It's back to being my DD for this week 'til I pick up my new Jeep.

Here's a quick cell phone video of some revs and idle - I can take other videos as needed and use the GoPro. I just unplugged the AIR fuse and relay (Since my system is missing due to the prior owner) then started it up like this:

 

Local shop hooked it up to their diagnostic laptop. Driver side, front o2 is bad. Got it in the mail yesterday. Will try to install it today at lunch time. The shop said he does not believe the o2 is causing the misfires though. I'm hoping it is, but we shall see...

 

I replaced the front driver side o2, recet ECU. Runs better, not the fix though. It has some weird electrical things going on. Shifted into reverse and the speedo jumped to 20 MPH. Opened the cutout and the RPM's jumped 300 RPM. 2 weeks ago the speedo was reading WAY low. 42 MPH when doing 70 for example.

 

Did you ever get this resolved?

 

Yeah just wondering also, mine sounds similar.

 

Nope. Next is going to be checking grounds and wiring some more...

 

Just wanted to update the latest. My buddy and I at work checked the wires running from the PCM to the coils. They all have continuity per our multi-meter. So, the wires are good from the PCM to the coils. One more thing ruled out I guess....

 

I would definitely clean all your grounds. What kind of voltage are you seeing when the car is running?

 

Voltage is normal. Right around 14.4 while running. Battery is 12.1 or so when off. We checked and the motor is ground very well. I need to physically see if the grounding straps on the rear of the block are good. What's the best way to get a visual?!

 

Ever consider pulling the valve covers and looking at the valve springs or doing a compression test?

 

The only reason I haven't gone that route is that it runs great sometimes and doesn't other times (Hot or cold). To me that rules out a mechanical problem.

 

Spray some carb cleaner around the intake and see if your idle changes. Might have bad intake gaskets causing the PO300.

 

Don't know if any of the Ford F 150 problems would maybe be the same as yours. But my truck had symtoms kinda like yours. And it was a coil pack. They said sometimes also Cracked eletronic firing sensor or throttle position sensor or Fuel pump control module.Don't know if this will help just a thought after reading your problem.That mystery stuff is the worst crap!

 

Sorry just watched your little video and mine was'nt like that, mine only missed when under a load 45-65 mph. Other wise cruising down highway at steady speed no problem and would idle smooth. But start to go up hill and step on pedal it would feel like misfire or like torque converter not working or something.If you took it out of overdrive it would go away even under load.

 

That is a horrible dead miss. I didn't see the video before my earlier post. You need to do a compression check on at least cylinder 5. Or at least pull the valve cover.