J30 Hesitates when warm

[madnance]

Hi, I have a 93 J30T. It has soaked me good recently for a tranny and injectors but I still love this car. After replacing the injectors, the mechanic forgot to hook up the vacuum line to the EGR valve. It ran great but engine light came on. He figured out what it was and hooked it back up. But now, once it warms up, it has a flat spot on the accelerator. From a stop, it starts fine, then as you press futher, nothing happens for about 1/4 pedal travel before it starts accelerating again. Its annoying. We tested it and removing the EGR valve made this go away again. I've looked at other sites and this seems like a common problem, but fixes were all over the map including changing plugs, coils, cleaning TB IAC(??), "Ohming" coils, replacing throttle position sensor, coolant temp sensor, crankshaft position snesore and cleaning the connectors ont the Mass Air Flow Sensor. Unfortunately, the engine light does not come on when the EGR is connected so the computer is no help.

Has anyone got any experience that would help me pinpoint this? How about just replacing the EGR valve?

Thanks for your thoughts,

Mad

[cshiremath]

Originally Posted by madnance

Hi, I have a 93 J30T. It has soaked me good recently for a tranny and injectors but I still love this car. After replacing the injectors, the mechanic forgot to hook up the vacuum line to the EGR valve. It ran great but engine light came on. He figured out what it was and hooked it back up. But now, once it warms up, it has a flat spot on the accelerator. From a stop, it starts fine, then as you press futher, nothing happens for about 1/4 pedal travel before it starts accelerating again. Its annoying. We tested it and removing the EGR valve made this go away again. I've looked at other sites and this seems like a common problem, but fixes were all over the map including changing plugs, coils, cleaning TB IAC(??), "Ohming" coils, replacing throttle position sensor, coolant temp sensor, crankshaft position snesore and cleaning the connectors ont the Mass Air Flow Sensor. Unfortunately, the engine light does not come on when the EGR is connected so the computer is no help.

Has anyone got any experience that would help me pinpoint this? How about just replacing the EGR valve?

Thanks for your thoughts,

Mad

I have the exact same problem like what you are describing. Please, please can you shed some light as to how you got the problem fixed.. Thanks, anticipating your response.
1994 - 240000 miles

[swimshark]

dang, you have 240000 on your '94. my '94 J has 82000

[madnance]

Chsiremath,

I wish I had the fix all sorted out but its part way there. The mechanic installed a delay valve on the EGR line so that it does not apply EGR immediately when youa ccelerate. The car runs great, and mileage is actually about 15% improved too. But the engine light still comes on. I need to see what the mechanic suggests next. I'm afraid that the EGR may not be working right and the engine light may be triggered by knocking. Let me know how your sleuthing is going. My J30 has 155K on it.

[cshiremath]

Hi madnance,
What kind of mileage (gas) does your car give? Mine is around the 18-20mpg mark. I have the engine light on too along with the exact problem of not accelerating for the initial 1/4th gas pedal travel. The frequency of this problem is noticable during summer moreso than winter. Moreover down here in LA (lower Alabama ) temperatures soar upto 90-100F

Thanks,
Chandru

[madnance]

Chandru, I got 18-22 MPG before the delay valve was intalled on the EGR, now I get 20-22. Its like too good to be true and I suspect something is not coming on with the air pump.

[cshiremath]

Thanks madnance I will get with my mechanic to discuss about the EGR valve. Did it cost a lot to get this fixed ($$$??)
Thanks,

[madnance]

Not for me but he treats me good. The valve was about $40.00.