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Skyvisions
Skyvisions, ASE Certified Technician
Category: Toyota
Satisfied Customers: 14357
Experience:  Toyota Master Diagnostic
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Backfiring stumbling under load, just started backfiring

Customer Question

backfiring stumbling under load
JA: Where exactly do you think the noise is coming from? And how long has this been going on?
Customer: just started backfiring through manifold
JA: What is the model/year of your Toyota?
Customer: 98 tacoma sr5 2.4 ltr
JA: Are you fixing your Tacoma yourself? What have you tried so far?
Customer: pulled throttle body-iac was carboned up--took apart cleaned thourouly
JA: Anything else you want the mechanic to know before I connect you?
Customer: runs fine til i hit the throttle then it falls on its face and backfires
Submitted: 2 months ago.
Category: Toyota
Expert:  Skyvisions replied 2 months ago.

Are you getting any codes set in the computer or has the check engine light been on? How many miles on the truck?

Customer: replied 2 months ago.
no codes--140000 miles
Customer: replied 2 months ago.
are you there?
Expert:  Skyvisions replied 2 months ago.

Sorry I had to step away from my computer for a little bit you check the timing on the camshaft to the crankshaft correlation? Did it jump time or have you run a cylinder complete test yet? Do you have any way to check the fuel pressure?

Customer: replied 2 months ago.
did you answer my question?
Expert:  Skyvisions replied 2 months ago.

I need more info from you did you get my reply?

Expert:  Skyvisions replied 2 months ago.

Did you check the timing on the camshaft to the crankshaft correlation? Did it jump time or have you run a cylinder complete test yet? Do you have any way to check the fuel pressure?

Customer: replied 2 months ago.
the cam time with the crank timing are as should be--it starts smooth but faulters at midrange--i just took the iac solenoid out dissasembled it from the throttle body--used a can of carb cleaner and thouroughly cleaned it--reassembled everything--it ran like a new one for about 45 minutes--then went back to its old tricks--stumbling at midrange
Customer: replied 2 months ago.
oh by the way it has 17 inches of vacuum at an idle
Expert:  Skyvisions replied 2 months ago.

17 inches of vacuum is not enough this engine should be in the neighborhood of 20 inches and 19 minimum. that indicates some type of intake leak did you check for intake leaks? When the problem occurs have you been able to monitor the fuel pressure to see if it's fluctuating below 35 PSI? Did you run a cylinder compression test yet

Customer: replied 2 months ago.
well i guess i got it its running 19 to 20 inches vacuum my iac was carboned up then just found the vacuum problem just took it for a test run--running fine--thanks joe
Expert:  Skyvisions replied 2 months ago.

that is good to hear Let me know if the problem comes back or if you need any additional assistance. If you have not done so please do not forget to rate the assistance that I provided to you at 3 or higher so that I may be compensated for my help today.