I have a 94 sunbird with a 2.0 and manual trans. About a month ago it started to have a little bit of a misfire under load. It always seemed to be at a certain position of the throttle (about half way to the floor) so I thought my TPS might have a dead spot or something. I wasn't sure so I took the car for a pretty hard drive and the problem went away. I figured I just had some carbon built up or something and called it good. The problem is that my car has developed the misfire again, not as bad as before but it's still there. I took the car for another hard drive yesterday and the problem didn't get any better this time. So I checked my TPS with a voltmeter. My Chilton's book says the voltage should be between .450 and 1.250, but mine is .40. Technically it's out of spec but would that little voltage difference cause my problem? I also checked the TPS for dead spots and didn't find any. Could it be my TPS or should I look elsewhere?





You can't outrun the radio.

chiltons book is wrong, .40 volts at closed throttle is normal. at WOT it should be over 4 volts. the important thing is that the voltage increases smoothly. with the voltmeter hooked up, slowly go from closed theottle to WOT and makse sure the voltage increases smoothly and doesnt jump at a certian point.

doesnt realy sound like a tps issue to me, but it is possible. it sounds like its missing at a certain load, and that would be more of an ignition or fuel problem.

sharkey wrote: make sure the voltage increases smoothly and doesn't jump at a certain point. /quote]

That is the way I was taught to check the TPS also. I dunno what else it could be, It has new plugs and newer wires. What confuses me is that it only does it at a certain load. Anybody have any ideas on what to check next?





You can't outrun the radio.

that could be somthing as simple as a misgapped sparkplug.


http://www.personal.psu.edu/users/a/t/atl126/ricers1.gif

94Custom wrote:that could be somthing as simple as a misgapped sparkplug.

They're new and gapped fine.





You can't outrun the radio.

first place Id look is the wires, but you said that you changed them. As long as you didnt put junky ones on, costing less than 20 bucks. Pull the fuel filter, see if the gas that you empty out of the tank side is dirty.


01 cav w/01 3400 gam gt 4t45e

I'd check for vacuum leaks! cracked or broken lines etc. since the plugs are new you could pull one after running some and see how it looks. smell it to see if it wreeks of gas anything out of the ordinary.

1990 Pontiac Sunbird GT turbo
-TGP turbo
-DSM SMIC turned TMIC
-Injectors

My car runs fantastic and the spark plug gap is .009 off!