Another hesitation / misfire / bogging / rattle rattle pop pop thread

[smackley]

More inspection into the spark issue on 3 &4. I guess at this point I'll keep a daily diary of my quest for folks to use in the future (Not that there aren't volumes out there already)

I pulled the plug on cyl 4 and attached the tension wire with the plug out of port to see if in fact there was no spark when I attempted to turn over the engine...no spark confirmed. I swapped the plug for the one on cyl 5 to see if it was just a bad/fouled plug. Cyl 5 continued to spark but no spark on 4, so not bad plugs. My cap/rotor comes in tomorrow so I'll post back after the swap. If this is the fix, I'll be very happy and yet very humbled at my erratic approach to solving this issue...

[Mr. Burns]

aaaaaaaaaaaand?

[smackley]

OK folks... car is running and problem solved. Here is what was wrong...

The old TPS had definitely failed. Once I replaced it, I took apart the old one and tested the micro switch controlling idle. It was stuck in "ON" mode so the ECU was getting an idle signal regardless of throttle position. This makes sense on the lean mixtures and misfire problem. The ICV would remain open at WOT and would let in too much air giving the ECU a hard time adjusting.

The next problem was the replacement of the injectors. I replaced my cap/rotor/wires with no fix in the dead cylinders. I pulled the fuel rail to see the injectors were receiving proper pulse signal. With the injectors in place on a loose fuel rail, I turned the car over and watched the injectors sequence. One injector was stuck in the open position and always dumped fuel, another was locked shut. They had failed. Got two replacements and the car fires right up, idles great, runs well.

I have some valve tick and I'm sure I'm overdue for a timing belt change, so this period of running well may be short lived before I have to pull valve cover and get and adjustment done...but I'll enjoy the vert while the sun shines.

[85e325]

Glad to hear you got it figured out. Makin me feel motivated to figure out why my 2.7L is running on the rich side. I think I have it pinpointed to injectors but now I just need to get off here for a few hours and pull em to confirm...