well im back with another problem with this truck. it acts like it wants to die at stop lights, bad gas millage, lacking power,
shakes at idle with brake on. but yet the check engine light does not come on. i know there is a problem. any suggestions? im also running 93 oct. this tank. but i dont think this has nothing to do with it. i have ran 93 before with no problems. i know the light works because when i turn the truck in the on position it comes on. please help. should i do a tune up? thanks rob

 

The PCM will still store a code but it will only turn on the SES light for an emissions related problem. Have the PCM read for any stored codes.

Regards

Jean Marc Chartier

 

The pcm will turn on the light for a number of reasons, sensor failure, trans problems, emission problems and misfires. Not just emissions. The emission problems will turn it on immediately as to where other problems may take up to two or more ignition cycles to appear.

Robbie

 

From the PCED: The malfunction indicator lamp (MIL) (Figure 14) alerts the driver that the powertrain control module (PCM) has detected an OBD II emission-related component or system fault. When this occurs, an OBD II Diagnostic Trouble Code (DTC) will be set.

JMC

 

thanks for the input. the pcm codes can be read with the the checker that plugs in under the dash right? just so we are on the right track here. The reason i ask is because when i had this checked before they couldnt find anything. maybe i wasnt asking for the samething or something. hell i dont know. thanks again. rob

 

Yes, the codes are read from the connector under the driver's side dash. There are 2 types of codes. DTC codes will cause the "check engine/service engine" light to come on. PENDING codes are stored but don't cause the light to come on until the problem occurs multiple times. Make sure the code scanner is capable of checking for PENDING codes also.

 

thanks man!! your guys input really helps!! i was scrolling through the Tranny section of the threads and found a reply of a guy who had a plug wire remedy for his tranny shutter. which i also have. so im thinking i have a related problem. now for a another question. this "coil on plug ingition" set-up, the plug wires are the 2 wires on top of coil pack right? how would you change them? which is the best plug, coils or wires to run? i called local auto part store and the coils are $54 each!! is this right? i going to need another job to afford the up keep on this truck!!! lol. thanks again. rob

 

Sounds like a COP problem, the wife's van had the same symptoms. Plug wires are not the two wires you see attached to the COP, those are part of the wiring harness going to your computer which signal the coil when to fire the plug. In fact, you don't have plug wires, but actually just a plug boot coming off the coil to the plug. There is tons of info about these beauties on this site. Good luck.

 

well i'm going to have a mechanic hook up one of those diagnostic computers to it tomorrow afternoon. I'll post a reply of what they found out. so if they found a coil problem what is one of those babies going to cost? should i just change the problem or put all new coils and plugs in? thanks for the input. rob

 

JMC, have you ever had a check engine light on with a transmission code ever lead you to an emissions related pinpoint test? Or did you not care to read the "system fault" portion of your post?

Robbie

 

well went to the "great mechanic" today. they said that they cant check it without light on. not to mention that the truck ran perfect all the way down and back. i hate this truck. its haunted. he just recommended changing plugs and inspecting the coils. he said if they had moisture or if they had rust in them to change them. ohwell. rob